further benchmarking stuff

This commit implements every algorithm I have played with so far. It also allows for you to switch which algorithm you want to use at runtime.

.gitignore

@@ -1 +0,0 @@
-node_modules

README.md

@@ -3,9 +3,9 @@
 Impost /ˈimˌpōst/ _noun_ a tax or compulsory payment
 
 Impost is a PoW anti-spam solution, or for short, a PoW captcha. Instead of
-spying on your users and using heavy captchas, Impost uses PoW to impose a cost
+spying on your users and using heavy, bloated captchas, Impost uses PoW to
-on sending requests. To a single user, this is a negligable few seconds, but at
+impose a cost on sending requests. To a single user, this is a negligable few
-scale, it can be a significant deterrent to spam.
+seconds, but at scale, it can be a significant deterrent to spam.
 
 This is the impost monorepo, containing the following packages:
 
@@ -14,6 +14,6 @@ This is the impost monorepo, containing the following packages:
 - `@impost/lib`: A library that can be used to generate, solve, and verify
   proofs.
 
-It also contains a `solver` package, which is the Zig PoW solver that
+It also contains a `solver` package, which is the PoW solver written in Zig,
-`@impost/lib` is built on top of, an example of how to use the solver in
+`@impost/lib` is built on top of, an example of how to use the solver in a
-example-app
+nuxt 3 project. More in-depth documentation will be added in the future.

example-app/.example.env

@@ -1 +1 @@
-IMPOST_HMAC_SECRET=xxx # openssl rand -base64 32
+YAPTCHA_HMAC_SECRET=xxx # openssl rand -base64 32

example-app/README.md

@@ -1,10 +1,10 @@
-# IMPOST
+# YAPTCHA
 
 Yet Another Pow capTCHA.
 
 ## What is this
 
-IMPOST is a proof of work based challenge-response system that is designed to
+YAPTCHA is a proof of work based challenge-response system that is designed to
 ward off spam and abuse.
 
 <!-- TODO: -->

example-app/app/pages/bench.vue

@@ -0,0 +1,187 @@
+<script setup lang="ts">
+let { data: challengeData } = await useFetch('/api/pow/challenge');
+let { data: powData } = await useFetch('/api/pow');
+
+if (!challengeData || !powData) {
+    throw createError({
+        statusCode: 500,
+        message: 'Failed to fetch data',
+    });
+}
+
+const algorithms = {
+    "argon2": {
+        name: 'argon2',
+        label: 'Argon2',
+        strategies: ['leading_zeroes', 'target_number'],
+    },
+    "kctf": {
+        name: 'kctf',
+        label: 'kCTF',
+        strategies: ['null'],
+    },
+    "sha256": {
+        name: 'sha256',
+        label: 'SHA256',
+        strategies: ['leading_zeroes', 'target_number'],
+    },
+};
+
+async function refresh() {
+    challengeData.value = await $fetch('/api/pow/challenge');
+    powData.value = await $fetch('/api/pow');
+
+    resetCaptcha();
+}
+
+function resetCaptcha() {
+    document.querySelector("pow-captcha")!.dispatchEvent(new CustomEvent('reset', {
+        detail: {
+            challenge: challengeData.value.challenge,
+        }
+    }));
+}
+
+let bench_results = ref([])
+let start = ref(0);
+let continue_bench: Promise<void> | null = null;
+
+async function bench() {
+    for (let algorithm_name in algorithms) {
+        let algorithm = algorithms[algorithm_name as "sha256" | "argon2" | "kctf"];
+        for (let strategy of algorithm.strategies) {
+            for (let i = 1; i <= 3; i++) {
+                // reduce statistical anomolies by running tests multiple times and averaging after tha fact
+                for (let j = 0; j < 5; j++) {
+                    let difficulty;
+                    switch (strategy) {
+                        case 'leading_zeroes':
+                            difficulty = i;
+                            break;
+                        case 'null':
+                        case 'target_number':
+                            // these tests scale linearly, so to try to match the
+                            // complexity of leading_zeroes, we grow the difficulty
+                            // exponentially
+                            difficulty = Math.pow(16, i);
+                            break;
+                    }
+                    await changeAlgorithm(algorithm_name);
+                    if (strategy !== 'null') {
+                        await changeStrategy(strategy);
+                    }
+                    await $fetch('/api/pow/difficulty', {
+                        method: 'PUT',
+                        body: JSON.stringify({
+                            difficulty: difficulty,
+                        }),
+                    })
+
+                    // sleep for 300ms
+                    await new Promise((resolve) => setTimeout(resolve, 750));
+
+                    await refresh();
+
+                    continue_bench = new Promise((resolve) => {
+                        document.querySelector("pow-captcha")!.addEventListener('impost:solved', () => {
+                            resolve();
+                        });
+                    });
+                    start.value = performance.now();
+                    document.querySelector("pow-captcha")!.dispatchEvent(new Event('solve'));
+                    await continue_bench;
+                    let end = performance.now();
+                    const data = {
+                        algorithm: algorithm_name,
+                        cores: navigator.hardwareConcurrency,
+                        strategy: strategy,
+                        difficulty: difficulty,
+                        time: end - start.value,
+                    };
+
+                    const should_scroll = document.documentElement.scrollTop + document.documentElement.clientHeight >= document.documentElement.scrollHeight;
+                    bench_results.value.push(data);
+                    if (should_scroll) {
+                        document.documentElement.scrollTop = document.documentElement.scrollHeight;
+                    }
+                }
+            }
+        }
+    }
+}
+
+function solved(ev: CustomEvent) {
+    console.log("Solved:", ev.detail.solution);
+}
+
+async function changeAlgorithmEV(ev: Event) {
+    changeAlgorithm(ev.target.value);
+
+    refresh();
+}
+
+async function changeAlgorithm(algorithm: string) {
+    await $fetch('/api/pow/algorithm', {
+        method: 'PUT',
+        body: JSON.stringify({
+            algorithm: algorithm
+        }),
+    });
+}
+
+async function changeStrategyEV(ev: Event) {
+    changeStrategy(ev.target.value);
+
+    refresh();
+}
+
+async function changeStrategy(strategy: string) {
+    await $fetch('/api/pow/strategy', {
+        method: 'PUT',
+        body: JSON.stringify({
+            strategy: strategy
+        }),
+    });
+}
+</script>
+
+<template>
+    <pow-captcha challengeUrl="/api/pow" :challengejson="JSON.stringify(challengeData!.challenge)"
+        @impost:solved="solved" />
+    <div class="flex flex-row gap-4">
+        <div class="flex flex-row gap-2" v-for="algorithm in algorithms" :key="algorithm.label">
+            <input type="radio" name="algorithm" @change="changeAlgorithmEV" :value="algorithm.name"
+                :id="algorithm.name" :checked="powData!.algorithm === algorithm.name"> <label :for="algorithm.name">{{
+                    algorithm.label
+                }}</label>
+        </div>
+    </div>
+    <div v-if="algorithms[powData!.algorithm].strategies.length > 1 && powData!.algorithm === algorithms[powData!.algorithm].name"
+        class="flex flex-row gap-4">
+        <div class="flex flex-row gap-2" v-for="strategy in algorithms[powData!.algorithm].strategies">
+            <input type="radio" name="strategy" @change="changeStrategyEV" :value="strategy" :id="strategy"
+                :checked="powData!.strategy === strategy"> <label :for="strategy">{{ strategy }}</label>
+        </div>
+    </div>
+    <input type="button" value="Start benchmark" @click="bench" />
+    <div v-if="bench_results.length > 0">
+        <table>
+            <thead>
+                <tr>
+                    <th>Algorithm</th>
+                    <th>Strategy</th>
+                    <th>Difficulty</th>
+                    <th>Time (ms)</th>
+                </tr>
+            </thead>
+            <tbody>
+                <tr v-for="result in bench_results" :key="result.algorithm + result.strategy + result.difficulty">
+                    <td>{{ algorithms[result.algorithm].label }}</td>
+                    <td>{{ result.strategy }}</td>
+                    <td>{{ result.difficulty }}</td>
+                    <td>{{ result.time }}</td>
+                </tr>
+            </tbody>
+        </table>
+    </div>
+</template>

example-app/app/pages/index.vue

@@ -9,7 +9,14 @@ if (!challengeData) {
 }
 
 function solved(ev: CustomEvent) {
-    console.log("Impost Solved:", ev.detail.solution);
+    console.log("Solved:", ev.detail.solution);
+    // $fetch('/api/pow/challenge', {
+    //     method: 'POST',
+    //     body: JSON.stringify({
+    //         challenge: ev.detail.challenge,
+    //         solution: ev.detail.solution,
+    //     }),
+    // });
 }
 
 function formsubmit(ev: Event) {
@@ -19,9 +26,9 @@ function formsubmit(ev: Event) {
 
 <template>
     <div class="flex justify-center items-center h-screen w-screen ">
-        <form @submit="formsubmit" action="/"
+        <form @submit.prevent="formsubmit"
             class="p-5 rounded-2xl bg-dark-9 border-coolGray-600 border flex flex-col gap-2">
-            <impost-captcha name="impost" challengeUrl="/api/pow" auto="onsubmit"
+            <pow-captcha challengeUrl="/api/pow" auto="onsubmit"
                 :challengejson="JSON.stringify(challengeData!.challenge)" @impost:solved="solved" />
             <input class="bg-blue-7 text-white font-semibold px-4 py-2.5 border-0 rounded-md" type="submit"
                 value="Submit" />

example-app/config.toml

@@ -1,7 +1,11 @@
+algorithm = "argon2"
 strategy = "target_number"
 
 [leading_zeroes]
-difficulty = 2
+difficulty = 4
 
 [target_number]
-max_number = 192
+max_number = 10000
+
+[kctf]
+difficulty = 100

example-app/nuxt.config.ts

@@ -19,7 +19,7 @@ export default defineNuxtConfig({
             }
         },
     },
-    modules: ['@unocss/nuxt', ['nuxt-ssr-lit', { litElementPrefix: 'impost-' }]],
+    modules: ['@unocss/nuxt', ['nuxt-ssr-lit', { litElementPrefix: 'pow-' }]],
 
     nitro: {
         moduleSideEffects: ["@impost/widget"],
@@ -28,9 +28,17 @@ export default defineNuxtConfig({
         },
     },
 
+    imports: {
+        transform: {
+            // only necessary in the monorepo since vite is going out to the
+            // source of the widget and transforming it and clobbering it.
+            exclude: [/impost/],
+        }
+    },
+
     vue: {
         compilerOptions: {
-            isCustomElement: (tag) => tag.startsWith('impost-'),
+            isCustomElement: (tag) => tag.includes('pow-'),
         },
     },
 

example-app/package.json

@@ -1,5 +1,5 @@
 {
-    "name": "example-app",
+    "name": "hello-nuxt",
     "private": true,
     "type": "module",
     "scripts": {
@@ -9,13 +9,15 @@
         "preview": "nuxt preview"
     },
     "dependencies": {
-        "@impost/lib": "workspace:*",
+        "@lit/reactive-element": "^2.1.1",
-        "@impost/widget": "workspace:*",
         "js-toml": "^1.0.2",
+        "lit-element": "^4.2.1",
+        "lit-html": "^3.3.1",
         "nuxt": "latest",
         "nuxt-ssr-lit": "1.6.32",
-        "vue": "^3.5.25",
+        "zod": "^4.1.12",
-        "zod": "^4.1.12"
+        "@impost/lib": "^0.1.0",
+        "@impost/widget": "^0.1.0"
     },
     "devDependencies": {
         "@types/node": "^24.10.0",

example-app/server/api/pow/algorithm.get.ts

@@ -0,0 +1,7 @@
+import { defineEventHandler } from 'h3'
+
+export default defineEventHandler((event) => {
+    return {
+        algorithm: config.algorithm
+    }
+})

example-app/server/api/pow/algorithm.put.ts

@@ -0,0 +1,43 @@
+import { defineEventHandler } from 'h3'
+import { ChallengeAlgorithm } from '@impost/lib';
+import * as z from 'zod';
+
+const algorithmSchema = z.object({
+    algorithm: z.enum(ChallengeAlgorithm),
+});
+
+export default defineEventHandler(async (event) => {
+    const body = await readValidatedBody(event, algorithmSchema.safeParse);
+
+    if (!body.success) {
+        throw createError({
+            statusCode: 400,
+            statusMessage: 'Validation failed'
+        })
+    }
+
+    switch (body.data.algorithm) {
+        case 'sha256':
+        case 'argon2':
+            config.algorithm = body.data.algorithm;
+            config.strategy = config.strategy || 'leading_zeroes';
+            switch (config.strategy) {
+                case 'leading_zeroes':
+                    config.leading_zeroes.difficulty = config.leading_zeroes.difficulty || 4;
+                    break;
+                case 'target_number':
+                    config.target_number.max_number = config.target_number.max_number || 10_000;
+                    break;
+            }
+            break;
+        case 'kctf':
+            config.algorithm = body.data.algorithm;
+            config.kctf = config.kctf || {};
+            config.kctf.difficulty = config.kctf.difficulty || 100;
+            break;
+    }
+
+    return {
+        message: `Algorithm set to ${config.algorithm}`
+    };
+});

example-app/server/api/pow/challenge.get.ts

@@ -1,25 +1,58 @@
 import { defineEventHandler } from 'h3'
 import { config } from '~~/server/utils/config';
-import { generate_challenge } from '@impost/lib/validator';
+import { generate_challenge, kCTFChallengeConfig, Argon2ChallengeConfig, SHA256ChallengeConfig } from '@impost/lib/validator';
-import { ChallengeStrategy } from '@impost/lib';
+import { ChallengeStrategy, ChallengeAlgorithm } from '@impost/lib';
 import { CHALLENGE_TIMEOUT_MS, outstandingChallenges } from '~~/server/utils/pow';
 
 export default defineEventHandler(async () => {
     let challenge_config;
+    switch (config.algorithm) {
+        case ChallengeAlgorithm.SHA256:
             switch (config.strategy) {
                 case ChallengeStrategy.LeadingZeroes:
                     challenge_config = {
-                parameters: { expires_at: CHALLENGE_TIMEOUT_MS },
+                        algorithm: ChallengeAlgorithm.SHA256,
-                strategy: config.strategy,
+                        strategy: ChallengeStrategy.LeadingZeroes,
-                difficulty: config.leading_zeroes?.difficulty!,
+                        difficulty: config.leading_zeroes.difficulty,
-            };
+                        parameters: { expires_at: Date.now() + CHALLENGE_TIMEOUT_MS },
+                    } as SHA256ChallengeConfig;
                     break;
                 case ChallengeStrategy.TargetNumber:
                     challenge_config = {
-                parameters: { expires_at: CHALLENGE_TIMEOUT_MS },
+                        algorithm: ChallengeAlgorithm.SHA256,
-                strategy: config.strategy,
+                        strategy: ChallengeStrategy.TargetNumber,
-                max_number: config.target_number.max_number,
+                        difficulty: config.target_number.max_number,
-            };
+                        parameters: { expires_at: Date.now() + CHALLENGE_TIMEOUT_MS },
+                    } as SHA256ChallengeConfig;
+                    break;
+            }
+            break;
+        case ChallengeAlgorithm.Argon2:
+            switch (config.strategy) {
+                case ChallengeStrategy.LeadingZeroes:
+                    challenge_config = {
+                        algorithm: ChallengeAlgorithm.Argon2,
+                        strategy: ChallengeStrategy.LeadingZeroes,
+                        difficulty: config.leading_zeroes.difficulty,
+                        parameters: { expires_at: Date.now() + CHALLENGE_TIMEOUT_MS },
+                    } as Argon2ChallengeConfig;
+                    break;
+                case ChallengeStrategy.TargetNumber:
+                    challenge_config = {
+                        algorithm: ChallengeAlgorithm.Argon2,
+                        strategy: ChallengeStrategy.TargetNumber,
+                        difficulty: config.target_number.max_number,
+                        parameters: { expires_at: Date.now() + CHALLENGE_TIMEOUT_MS },
+                    } as Argon2ChallengeConfig;
+                    break;
+            }
+            break;
+        case ChallengeAlgorithm.kCTF:
+            challenge_config = {
+                algorithm: ChallengeAlgorithm.kCTF,
+                difficulty: config.kctf.difficulty,
+                parameters: { expires_at: Date.now() + CHALLENGE_TIMEOUT_MS },
+            } as kCTFChallengeConfig;
             break;
     }
 

example-app/server/api/pow/challenge.post.ts

@@ -4,8 +4,9 @@ import * as z from 'zod';
 import { outstandingChallenges } from '~~/server/utils/pow';
 
 const challengeSchema = z.object({
-    challenge: z.string(),
+    salt: z.string(),
-    nonce: z.string()
+    // either a string if the algorithm is kCTF, or a number if the algorithm is Argon2 or SHA256
+    solution: z.string().or(z.number()),
 })
 
 // post handler that takes in the challenge, and the nonce
@@ -13,29 +14,32 @@ export default defineEventHandler(async (event) => {
     const body = await readValidatedBody(event, challengeSchema.safeParse);
 
     if (!body.success) {
-        const errors = z.treeifyError(body.error);
-        const error_message = Object.entries(errors.errors).map(([key, value]) => `${key}: ${value}`).join('\n');
-
         throw createError({
             statusCode: 400,
-            statusMessage: error_message
+            statusMessage: 'Validation failed'
         })
     }
 
-    let { challenge, nonce } = body.data;
+    let { salt, solution } = body.data;
 
-    const outstanding_challenge = outstandingChallenges.get(body.data.challenge)!;
+    const outstanding_challenge = outstandingChallenges.get(salt);
-    // always delete the challenge on a solve attempt
+    if (outstanding_challenge === undefined) {
-    clearTimeout(outstanding_challenge.timeout);
+        throw createError({
-    outstandingChallenges.delete(challenge);
+            statusCode: 400,
+            statusMessage: 'Challenge not found'
+        })
+    }
 
     // check if the challenge is valid
-    let challenge_valid = await validate_challenge(outstandingChallenges.get(challenge)!.challenge, {
+    const challenge_valid = await validate_challenge(outstanding_challenge.challenge, solution);
-        challenge,
+
-        nonce,
+    console.log("CHALLENGE VALID", challenge_valid);
-    });
 
     if (challenge_valid) {
+        // clear the challenge
+        clearTimeout(outstandingChallenges.get(salt)!.timeout);
+        outstandingChallenges.delete(salt);
+
         return {
             message: 'Challenge solved'
         };

example-app/server/api/pow/difficulty.get.ts

@@ -1,9 +1,14 @@
 import { defineEventHandler } from 'h3'
-import { ChallengeStrategy } from '@impost/lib';
+import { ChallengeStrategy, ChallengeAlgorithm } from '@impost/lib';
 
 export default defineEventHandler((event) => {
     let difficulty: number;
 
+    console.log("CONFIG", config);
+
+    switch (config.algorithm) {
+        case ChallengeAlgorithm.SHA256:
+        case ChallengeAlgorithm.Argon2:
             switch (config.strategy) {
                 case ChallengeStrategy.LeadingZeroes:
                     difficulty = config.leading_zeroes.difficulty!;
@@ -12,6 +17,11 @@ export default defineEventHandler((event) => {
                     difficulty = config.target_number.max_number!;
                     break;
             }
+            break;
+        case ChallengeAlgorithm.kCTF:
+            difficulty = config.kctf.difficulty!;
+            break;
+    }
 
     return {
         difficulty

example-app/server/api/pow/difficulty.put.ts

@@ -1,11 +1,14 @@
 import { defineEventHandler } from 'h3'
-import { ChallengeStrategy } from '@impost/lib';
+import { ChallengeStrategy, ChallengeAlgorithm } from '@impost/lib';
 
 export default defineEventHandler(async (event) => {
     const body = await readBody(event)
 
     let difficulty = body.difficulty;
 
+    switch (config.algorithm) {
+        case ChallengeAlgorithm.SHA256:
+        case ChallengeAlgorithm.Argon2:
             switch (config.strategy) {
                 case ChallengeStrategy.LeadingZeroes:
                     if (!difficulty || difficulty < 1 || difficulty > 64) {
@@ -28,8 +31,13 @@ export default defineEventHandler(async (event) => {
                     config.target_number.max_number = difficulty;
                     break;
             }
+            break;
+        case ChallengeAlgorithm.kCTF:
+            config.kctf.difficulty = difficulty;
+            break;
+    }
 
     return {
-        message: 'Challenge difficulty set'
+        message: `Challenge difficulty set to ${difficulty}`
     };
 });

example-app/server/api/pow/index.get.ts

@@ -0,0 +1,35 @@
+import { ChallengeAlgorithm } from '@impost/lib';
+import { defineEventHandler } from 'h3'
+
+export default defineEventHandler((event) => {
+    let difficulty: number;
+
+    switch (config.algorithm) {
+        case ChallengeAlgorithm.SHA256:
+        case ChallengeAlgorithm.Argon2:
+            switch (config.strategy) {
+                case 'leading_zeroes':
+                    difficulty = config.leading_zeroes.difficulty!;
+                    break;
+                case 'target_number':
+                    difficulty = config.target_number.max_number!;
+                    break;
+            }
+            break;
+        case ChallengeAlgorithm.kCTF:
+            difficulty = config.kctf.difficulty!;
+            break;
+        default:
+            throw createError({
+                statusCode: 500,
+                statusMessage: 'Unknown algorithm',
+            })
+            break;
+    }
+
+    return {
+        difficulty,
+        algorithm: config.algorithm,
+        strategy: config.strategy || undefined,
+    }
+})

example-app/server/api/pow/strategy.get.ts

@@ -0,0 +1,14 @@
+import { defineEventHandler } from "h3";
+import { ChallengeAlgorithm } from "@impost/lib";
+
+export default defineEventHandler(async (event) => {
+    if (config.algorithm === ChallengeAlgorithm.kCTF) {
+        return {
+            strategy: undefined,
+        }
+    }
+
+    return {
+        strategy: config.strategy,
+    }
+});

example-app/server/api/pow/strategy.put.ts

@@ -0,0 +1,43 @@
+import { defineEventHandler } from 'h3'
+import { ChallengeAlgorithm, ChallengeStrategy } from '@impost/lib';
+import * as z from 'zod';
+
+const strategySchema = z.object({
+    strategy: z.enum(ChallengeStrategy),
+});
+
+export default defineEventHandler(async (event) => {
+    const body = await readValidatedBody(event, strategySchema.safeParse);
+
+    if (!body.success) {
+        throw createError({
+            statusCode: 400,
+            statusMessage: 'Validation failed'
+        })
+    }
+
+    switch (config.algorithm) {
+        case ChallengeAlgorithm.SHA256:
+        case ChallengeAlgorithm.Argon2:
+            config.strategy = body.data.strategy;
+            switch (config.strategy) {
+                case ChallengeStrategy.LeadingZeroes:
+                    config.leading_zeroes = config.leading_zeroes || {};
+                    config.leading_zeroes.difficulty = config.leading_zeroes.difficulty || 4;
+                    break;
+                case ChallengeStrategy.TargetNumber:
+                    config.target_number = config.target_number || {};
+                    config.target_number.max_number = config.target_number.max_number || 10_000;
+                    break;
+            }
+            break;
+        case ChallengeAlgorithm.kCTF:
+            return {
+                message: "Strategy cannot be set for kCTF"
+            }
+    }
+
+    return {
+        message: `Strategy set to ${config.strategy}`
+    };
+});

example-app/server/utils/config.ts

@@ -1,30 +1,53 @@
 import { readFileSync } from 'fs';
 import { load } from 'js-toml';
 import z from 'zod';
-import { ChallengeStrategy } from "@impost/lib";
+import { ChallengeAlgorithm, ChallengeStrategy } from "@impost/lib";
 
-const LeadingZeroesSchema = z.object({
+const SHA256Schema = z.discriminatedUnion("strategy", [
+    z.object({
+        algorithm: z.literal(ChallengeAlgorithm.SHA256),
         strategy: z.literal(ChallengeStrategy.LeadingZeroes),
         leading_zeroes: z.object({
             difficulty: z.number().int().min(1).max(64),
         }),
-});
+    }),
-
+    z.object({
-const TargetNumberSchema = z.object({
+        algorithm: z.literal(ChallengeAlgorithm.SHA256),
         strategy: z.literal(ChallengeStrategy.TargetNumber),
         target_number: z.object({
             max_number: z.number().int().min(1).max(100_000),
         }),
+    }),
+]);
+
+const Argon2Schema = z.discriminatedUnion("strategy", [
+    z.object({
+        algorithm: z.literal(ChallengeAlgorithm.Argon2),
+        strategy: z.literal(ChallengeStrategy.LeadingZeroes),
+        leading_zeroes: z.object({
+            difficulty: z.number().int().min(1).max(64),
+        }),
+    }),
+    z.object({
+        algorithm: z.literal(ChallengeAlgorithm.Argon2),
+        strategy: z.literal(ChallengeStrategy.TargetNumber),
+        target_number: z.object({
+            max_number: z.number().int().min(1).max(100_000),
+        }),
+    }),
+]);
+
+const KCTFSchema = z.object({
+    algorithm: z.literal(ChallengeAlgorithm.kCTF),
+    kctf: z.object({
+        difficulty: z.number().int().min(1),
+    }),
 });
 
+export const Config = z.union([SHA256Schema, Argon2Schema, KCTFSchema]);
 
 export type Config = z.infer<typeof Config>;
 
-export const Config = z.discriminatedUnion('strategy', [
-    LeadingZeroesSchema,
-    TargetNumberSchema,
-]);
-
 export let config: Config;
 
 try {

justfile

@@ -0,0 +1,30 @@
+wasm-opt-args := "--strip-debug --strip-dwarf --enable-tail-call --enable-bulk-memory -Oz"
+zig-build-args := "--release=fast -Dtarget=wasm32-freestanding -Dcpu=generic+bulk_memory+bulk_memory_opt+simd128+tail_call"
+
+npm-runner := "npm"
+
+[working-directory: "example-app"]
+playground: build
+    {{npm-runner}} run dev
+
+build: build-widget
+
+[working-directory: "solver"]
+build-wasm:
+    zig build {{zig-build-args}}
+    wasm-opt {{wasm-opt-args}} --enable-simd -o zig-out/bin/solver.wasm zig-out/bin/solver.wasm
+    # The server does not support simd, so we disable it here
+    wasm-opt {{wasm-opt-args}} --disable-simd -o zig-out/bin/validator.wasm zig-out/bin/validator.wasm
+
+[working-directory: "packages/lib"]
+build-lib: build-wasm
+    {{npm-runner}} install
+    {{npm-runner}} link
+    {{npm-runner}} run build
+
+[working-directory: "packages/widget"]
+build-widget: build-lib
+    {{npm-runner}} install
+    {{npm-runner}} link @impost/lib
+    {{npm-runner}} link
+    {{npm-runner}} run build

package.json

@@ -1,17 +0,0 @@
-{
-    "name": "impost-monorepo",
-    "version": "0.0.0",
-    "private": true,
-    "scripts": {
-        "build": "pnpm build:all",
-        "build:all": "pnpm build:solver && pnpm build:lib && pnpm build:widget",
-        "build:solver": "pnpm --filter solver build",
-        "build:lib": "pnpm --filter lib build",
-        "build:widget": "pnpm --filter widget build",
-        "dev:example": "pnpm --filter example-app dev"
-    },
-    "devDependencies": {
-        "typescript": "^5.0.0"
-    },
-    "packageManager": "pnpm@10.21.0+sha512.da3337267e400fdd3d479a6c68079ac6db01d8ca4f67572083e722775a796788a7a9956613749e000fac20d424b594f7a791a5f4e2e13581c5ef947f26968a40"
-}

packages/lib/src/index.ts

@@ -1,16 +1,43 @@
+import { UUID } from "uuidv7";
+
 export enum ChallengeAlgorithm {
-    Argon2id = "argon2id",
+    SHA256 = "sha256",
+    Argon2 = "argon2",
+    kCTF = "kctf",
+}
+
+export function algorithmToInt(algorithm: ChallengeAlgorithm): number {
+    switch (algorithm) {
+        case ChallengeAlgorithm.SHA256:
+            return 0;
+        case ChallengeAlgorithm.Argon2:
+            return 1;
+        case ChallengeAlgorithm.kCTF:
+            return 2;
+    }
 }
 
 export enum ChallengeStrategy {
+    Null = "null",
     LeadingZeroes = "leading_zeroes",
     TargetNumber = "target_number",
 }
 
+export function strategyToInt(strategy: ChallengeStrategy): number {
+    switch (strategy) {
+        case ChallengeStrategy.Null:
+            return 0;
+        case ChallengeStrategy.LeadingZeroes:
+            return 1;
+        case ChallengeStrategy.TargetNumber:
+            return 2;
+    }
+}
+
 // In this case, the client will repeatedly hash a number with has until it 
 // finds a hash thaat starts with *difficulty* leading zeroes
 export interface ChallengeLeadingZeroes {
-    algorithm: ChallengeAlgorithm;
+    algorithm: ChallengeAlgorithm.SHA256 | ChallengeAlgorithm.Argon2;
     strategy: ChallengeStrategy.LeadingZeroes;
     salt: string; // random string
     difficulty: number;
@@ -19,10 +46,24 @@ export interface ChallengeLeadingZeroes {
 // In this case, the server generates a random number, and the client will hash
 // the salt (a random string) + a random number until it finds a hash that is equal to challenge
 export interface ChallengeTargetNumber {
-    algorithm: ChallengeAlgorithm;
+    algorithm: ChallengeAlgorithm.SHA256 | ChallengeAlgorithm.Argon2;
     strategy: ChallengeStrategy.TargetNumber;
     salt: string; // random string
     target: string; // hash of salt + random number
 }
 
-export type Challenge = ChallengeLeadingZeroes | ChallengeTargetNumber;
+export interface InnerChallengekCTF {
+    algorithm: ChallengeAlgorithm.kCTF;
+    salt: UUID; // UUIDv7
+    difficulty: number;
+}
+
+export interface ChallengekCTF {
+    algorithm: ChallengeAlgorithm.kCTF;
+    salt: string;
+    difficulty: number;
+}
+
+export type InnerChallenge = InnerChallengekCTF | ChallengeLeadingZeroes | ChallengeTargetNumber;
+
+export type Challenge = ChallengekCTF | ChallengeLeadingZeroes | ChallengeTargetNumber;

packages/lib/src/solver.ts

@@ -1,11 +1,10 @@
-import WASMSolverUrl from '../../solver/zig-out/bin/solver.wasm?url&inline';
+import { ChallengeAlgorithm, ChallengeStrategy, algorithmToInt, strategyToInt } from "./index";
-import { ChallengeStrategy, type Challenge, type ChallengeLeadingZeroes, type ChallengeTargetNumber } from '.';
+import WASMSolverUrl from '../../../solver/zig-out/bin/solver.wasm?url&inline';
 
 type WasmExports = Record<string, Function> & {
     "malloc": (byte_count: number) => number | null;
     "free": (ptr: number | null, byte_count: number) => void;
-    "solve_leaading_zeroes_challenge": (challenge_ptr: number, challenge_len: number, difficulty: number) => number;
+    "solve": (algorithm: number, strategy: number, salt_ptr: number, salt_len: number, difficulty: number, target_ptr: number, target_len: number) => number,
-    "solve_target_number_challenge": (challenge_ptr: number, challenge_len: number, target_ptr: number, target_len: number) => number;
     "memory": WebAssembly.Memory;
 }
 
@@ -31,75 +30,100 @@ export async function init_solver(env: SolverEnv, module: WebAssembly.Module): P
     }) as unknown as SolverModule;
 }
 
-export function solve_challenge(solver: SolverModule, challenge: Challenge): number {
+type Argon2LeadingZeroesParams = {
-    switch (challenge.strategy) {
+    name: ChallengeAlgorithm.Argon2;
-        case ChallengeStrategy.LeadingZeroes:
+    strategy: ChallengeStrategy.LeadingZeroes;
-            return solve_leaading_zeroes_challenge(solver, challenge);
+    salt: string;
-        case ChallengeStrategy.TargetNumber:
+    difficulty: number;
-            return solve_target_number_challenge(solver, challenge);
+};
-        default:
+
-            throw new Error("Invalid challenge strategy");
+type Argon2TargetNumberParams = {
-    }
+    name: ChallengeAlgorithm.Argon2;
+    strategy: ChallengeStrategy.TargetNumber;
+    salt: string;
+    target: string;
+};
+
+type Argon2Params = Argon2LeadingZeroesParams | Argon2TargetNumberParams;
+
+type SHA256LeadingZeroesParams = {
+    name: ChallengeAlgorithm.SHA256;
+    strategy: ChallengeStrategy.LeadingZeroes;
+    salt: string;
+    difficulty: number;
+};
+
+type SHA256TargetNumberParams = {
+    name: ChallengeAlgorithm.SHA256;
+    strategy: ChallengeStrategy.TargetNumber;
+    salt: string;
+    target: string;
+};
+
+type SHA256Params = SHA256LeadingZeroesParams | SHA256TargetNumberParams;
+
+type KCTFParams = {
+    name: ChallengeAlgorithm.kCTF;
+    strategy: ChallengeStrategy.Null;
+    salt: string;
+    difficulty: number;
+};
+
+export type SolveParams = Argon2Params | SHA256Params | KCTFParams;
+
+export function solve(solver: SolverModule, algorithm: SolveParams): string | number {
+    if (algorithm.name === ChallengeAlgorithm.kCTF) {
+        algorithm.salt = algorithm.salt.split("?")[0];
     }
 
-function solve_leaading_zeroes_challenge(solver: SolverModule, challenge: ChallengeLeadingZeroes): number {
-    const { salt, difficulty } = challenge;
     const encoder = new TextEncoder();
+    let salt_buf = encoder.encode(algorithm.salt);
 
-    const salt_bytes = encoder.encode(salt);
+    let salt_ptr = solver.exports.malloc(salt_buf.length);
-
-    const salt_ptr = solver.exports.malloc(salt_bytes.length);
     if (salt_ptr === 0 || salt_ptr === null) {
         throw new Error("Failed to allocate memory for challenge string");
     }
 
-    const memory = new Uint8Array(solver.exports.memory.buffer);
+    let memory = new Uint8Array(solver.exports.memory.buffer);
-    memory.set(salt_bytes, salt_ptr);
+    memory.set(salt_buf, salt_ptr);
 
-    const ret = solver.exports.solve_leaading_zeroes_challenge(
+    let ret: string | number;
-        salt_ptr,
+    switch (algorithm.name) {
-        salt_bytes.length,
+        case ChallengeAlgorithm.SHA256:
-        difficulty,
+        case ChallengeAlgorithm.Argon2:
-    );
+            switch (algorithm.strategy) {
-
+                case ChallengeStrategy.LeadingZeroes: {
-    if (ret < 0) {
+                    ret = solver.exports.solve(algorithmToInt(algorithm.name), strategyToInt(ChallengeStrategy.LeadingZeroes), salt_ptr, salt_buf.length, algorithm.difficulty, 0, 0);
-        throw new Error("Failed to solve challenge");
+                    break;
                 }
-
+                case ChallengeStrategy.TargetNumber: {
-    return ret;
+                    const target_buf = encoder.encode(algorithm.target);
-}
+                    const target_ptr = solver.exports.malloc(target_buf.length);
-
-function solve_target_number_challenge(solver: SolverModule, challenge: ChallengeTargetNumber): number {
-    const { salt, target } = challenge;
-    const encoder = new TextEncoder();
-
-    const salt_bytes = encoder.encode(salt);
-    const target_bytes = encoder.encode(target);
-
-    const salt_ptr = solver.exports.malloc(salt_bytes.length);
-    if (salt_ptr === 0 || salt_ptr === null) {
-        throw new Error("Failed to allocate memory for salt string");
-    }
-
-    const target_ptr = solver.exports.malloc(target_bytes.length);
                     if (target_ptr === 0 || target_ptr === null) {
                         throw new Error("Failed to allocate memory for target string");
                     }
 
-    const memory = new Uint8Array(solver.exports.memory.buffer);
+                    memory = new Uint8Array(solver.exports.memory.buffer);
-    memory.set(salt_bytes, salt_ptr);
+                    memory.set(target_buf, target_ptr);
-    memory.set(target_bytes, target_ptr);
 
-    const ret = solver.exports.solve_target_number_challenge(
+                    ret = solver.exports.solve(algorithmToInt(algorithm.name), strategyToInt(ChallengeStrategy.TargetNumber), salt_ptr, salt_buf.length, 0, target_ptr, target_buf.length);
-        target_ptr,
+                    break;
-        target_bytes.length,
+                }
-        salt_ptr,
+            }
-        salt_bytes.length,
+            break;
-    );
+        case ChallengeAlgorithm.kCTF:
+            const solution_ptr = solver.exports.solve(algorithmToInt(ChallengeAlgorithm.kCTF), strategyToInt(ChallengeStrategy.Null), salt_ptr, salt_buf.length, algorithm.difficulty, 0, 0);
 
-    if (ret < 0) {
+            if (solution_ptr <= 0) {
                 throw new Error("Failed to solve challenge");
             }
 
+            const length = new DataView(solver.exports.memory.buffer, solution_ptr, 2).getUint16(0, true);
+            ret = new TextDecoder().decode(solver.exports.memory.buffer.slice(solution_ptr + 2, solution_ptr + 2 + length));
+
+            solver.exports.free(solution_ptr, 2 + length);
+            break;
+    }
+
     return ret;
 }

packages/lib/src/validator.ts

@@ -1,12 +1,12 @@
-import { ChallengeAlgorithm, ChallengeStrategy, type Challenge, type ChallengeLeadingZeroes, type ChallengeTargetNumber } from '.';
+import { ChallengeStrategy, type Challenge, type InnerChallenge, ChallengeAlgorithm, algorithmToInt, strategyToInt } from '.';
-import WASMValidatorUrl from '../../solver/zig-out/bin/validator.wasm?url&inline';
+import WASMValidatorUrl from '../../../solver/zig-out/bin/validator.wasm?url&inline';
+import { uuidv7obj } from 'uuidv7';
 
 type WasmExports = Record<string, Function> & {
     "malloc": (byte_count: number) => number | null;
     "free": (ptr: number | null, byte_count: number) => void;
-    "validate_leading_zeroes_challenge": (challenge_ptr: number, challenge_len: number, nonce_ptr: number, nonce_len: number, difficulty: number) => number;
+    "validate": (algorithm: number, strategy: number, challenge_ptr: number, challenge_len: number, solution_ptr: number, solution_len: number, nonce: number, difficulty: number) => boolean;
-    "validate_target_number_challenge": (target_ptr: number, target_len: number, nonce_ptr: number, nonce_len: number, salt_ptr: number, salt_len: number) => number;
+    "hash": (challenge_ptr: number, challebge_len: number, nonce_ptr: number, nonce_len: number, algorithm: number) => bigint;
-    "hash": (challenge_ptr: number, challenge_len: number, nonce_ptr: number, nonce_len: number) => bigint;
     "memory": WebAssembly.Memory;
 }
 
@@ -14,159 +14,281 @@ export interface ValidatorModule extends WebAssembly.Instance {
     exports: WasmExports;
 }
 
-function array_to_base64(buffer: ArrayBuffer): string {
+function array_to_base64(buffer: ArrayBufferLike): string {
-    return btoa(String.fromCharCode(...new Uint8Array(buffer)));
+    let binary = '';
+    const bytes = new Uint8Array(buffer);
+    for (var i = 0; i < bytes.byteLength; i++) {
+        binary += String.fromCharCode(bytes[i]);
+    }
+    return btoa(binary);
 }
 
-async function generate_leading_zeroes_challenge(parameters: Object, difficulty: number): Promise<ChallengeLeadingZeroes> {
+export interface SHA256ChallengeConfig {
-    let parameters_str = Object.entries(parameters).map(([key, value]) => `${key}=${value}`).join("&");
+    algorithm: ChallengeAlgorithm.SHA256;
-    let salt = `${array_to_base64(crypto.getRandomValues(new Uint8Array(32)).buffer)}?${parameters_str}`;
+    strategy: ChallengeStrategy.LeadingZeroes | ChallengeStrategy.TargetNumber;
+    difficulty: number;
+    parameters: Object;
+}
 
-    let challenge: ChallengeLeadingZeroes = {
+export interface Argon2ChallengeConfig {
-        algorithm: ChallengeAlgorithm.Argon2id,
+    algorithm: ChallengeAlgorithm.Argon2;
-        strategy: ChallengeStrategy.LeadingZeroes,
+    strategy: ChallengeStrategy.LeadingZeroes | ChallengeStrategy.TargetNumber;
-        salt,
+    difficulty: number;
-        difficulty,
+    parameters: Object;
-    };
+}
+
+export interface kCTFChallengeConfig {
+    algorithm: ChallengeAlgorithm.kCTF;
+    difficulty: number;
+    parameters: Object;
+}
+
+export type ChallengeConfig = kCTFChallengeConfig | SHA256ChallengeConfig | Argon2ChallengeConfig;
+
+async function encode_challenge(inner_challenge: InnerChallenge, parameters: Object = {}): Promise<Challenge> {
+    let challenge: Challenge = {} as Challenge;
+    switch (inner_challenge.algorithm) {
+        case ChallengeAlgorithm.SHA256: {
+            challenge.algorithm = ChallengeAlgorithm.SHA256;
+            challenge.salt = inner_challenge.salt;
+            switch (inner_challenge.strategy) {
+                case ChallengeStrategy.LeadingZeroes: {
+                    // @ts-ignore
+                    challenge.strategy = ChallengeStrategy.LeadingZeroes;
+                    // @ts-ignore
+                    challenge.difficulty = inner_challenge.difficulty;
+                    break;
+                }
+                case ChallengeStrategy.TargetNumber: {
+                    // @ts-ignore
+                    challenge.strategy = ChallengeStrategy.TargetNumber;
+                    // @ts-ignore
+                    challenge.target = inner_challenge.target;
+                    break;
+                }
+            }
+            break;
+        }
+        case ChallengeAlgorithm.Argon2: {
+            challenge.algorithm = ChallengeAlgorithm.Argon2;
+            challenge.salt = inner_challenge.salt;
+            switch (inner_challenge.strategy) {
+                case ChallengeStrategy.LeadingZeroes: {
+                    // @ts-ignore
+                    challenge.strategy = ChallengeStrategy.LeadingZeroes;
+                    // @ts-ignore
+                    challenge.difficulty = inner_challenge.difficulty;
+                    break;
+                }
+                case ChallengeStrategy.TargetNumber: {
+                    // @ts-ignore
+                    challenge.strategy = ChallengeStrategy.TargetNumber;
+                    // @ts-ignore
+                    challenge.target = inner_challenge.target;
+                    break;
+                }
+            }
+            break;
+        }
+        case ChallengeAlgorithm.kCTF: {
+            // @ts-ignore
+            challenge.difficulty = inner_challenge.difficulty;
+            challenge.algorithm = ChallengeAlgorithm.kCTF;
+            challenge.salt = array_to_base64(inner_challenge.salt.bytes.buffer);
+            break;
+        }
+    }
+
+    // the parameters str is expected to be sliced out of the challenge via the widget before it sends it to the wasm solver.
+    let parameters_str = Object.entries(parameters).map(([key, value]) => `${key}=${value}`).join("&");
+    if (parameters_str.length > 0) {
+        parameters_str = "?" + parameters_str;
+    }
+
+    challenge.salt = challenge.salt + parameters_str;
 
     return challenge;
 }
 
-async function generate_target_number_challenge(parameters: Object, max_number: number): Promise<ChallengeTargetNumber | null> {
+export async function generate_challenge(config: ChallengeConfig): Promise<Challenge | null> {
-    // in target number config, since we need to generate a target hash, we
+    if (config.difficulty < 1) {
-    // need to hash the salt + nonce, so the client knows what the target is
+        throw new Error("Difficulty must be at least 1");
-    const validator = (await WebAssembly.instantiateStreaming(fetch(WASMValidatorUrl))).instance as unknown as ValidatorModule;
+    }
 
-    let parameters_str = Object.entries(parameters).map(([key, value]) => `${key}=${value}`).join("&");
+    const validator = (await WebAssembly.instantiateStreaming(fetch(WASMValidatorUrl), {
-    let salt = `${array_to_base64(crypto.getRandomValues(new Uint8Array(32)).buffer)}?${parameters_str}`;
+        env: {
-    let random_number = new DataView(crypto.getRandomValues(new Uint8Array(4)).buffer).getUint32(0, true) % max_number;
+            __log: (str_ptr: number, str_len: number) => console.log(new TextDecoder().decode(new Uint8Array(validator.exports.memory.buffer, str_ptr, str_len))),
+        }
+    })).instance as unknown as ValidatorModule;
 
     const encoder = new TextEncoder();
-    const salt_bytes = encoder.encode(salt);
-    const random_number_bytes = encoder.encode(random_number.toString());
 
-    const salt_ptr = validator.exports.malloc(salt_bytes.length);
+    var inner_challenge: InnerChallenge = {
-    const random_number_ptr = validator.exports.malloc(random_number_bytes.length);
+        algorithm: config.algorithm,
+    } as InnerChallenge;
+    let salt = `${array_to_base64(crypto.getRandomValues(new Uint8Array(32)).buffer)}`;
+    let parameters_str: string;
+    switch (config.algorithm) {
+        case ChallengeAlgorithm.SHA256:
+        case ChallengeAlgorithm.Argon2:
+            switch (config.strategy) {
+                case ChallengeStrategy.LeadingZeroes:
+                    if (config.difficulty < 1 || config.difficulty > 64) {
+                        throw new Error("Invalid difficulty for leading zeroes strategy");
+                    }
 
-    if (salt_ptr === 0 || salt_ptr === null || random_number_ptr === 0 || random_number_ptr === null) {
+                    // @ts-ignore
+                    inner_challenge.strategy = ChallengeStrategy.LeadingZeroes;
+                    // @ts-ignore
+                    inner_challenge.difficulty = config.difficulty;
+                    parameters_str = Object.entries(config.parameters).map(([key, value]) => `${key}=${value}`).join("&");
+                    if (parameters_str.length > 0) {
+                        parameters_str = "?" + parameters_str;
+                    }
+                    inner_challenge.salt = salt + parameters_str;
+                    config.parameters = {};
+                    break;
+                case ChallengeStrategy.TargetNumber:
+                    if (config.difficulty < 1) {
+                        throw new Error("Difficulty must be at least 1");
+                    }
+
+                    // @ts-ignore
+                    inner_challenge.strategy = ChallengeStrategy.TargetNumber;
+                    parameters_str = Object.entries(config.parameters).map(([key, value]) => `${key}=${value}`).join("&");
+                    if (parameters_str.length > 0) {
+                        parameters_str = "?" + parameters_str;
+                    }
+                    inner_challenge.salt = salt + parameters_str;
+                    config.parameters = {};
+
+                    const random_number = Math.floor(Math.random() * config.difficulty).toString();
+                    console.log("RANDOM NUMBER", random_number);
+
+                    const challenge_buf = encoder.encode(inner_challenge.salt + random_number);
+                    const challenge_ptr = validator.exports.malloc(challenge_buf.length);
+                    if (challenge_ptr === 0 || challenge_ptr === null) {
                         console.error("Failed to allocate memory for challenge string");
                         return null;
                     }
 
                     const memory = new Uint8Array(validator.exports.memory.buffer);
-    memory.set(salt_bytes, salt_ptr);
+                    memory.set(challenge_buf, challenge_ptr);
-    memory.set(random_number_bytes, random_number_ptr);
 
-    let target_blob: bigint = validator.exports.hash(salt_ptr, salt_bytes.length, random_number_ptr, random_number_bytes.length);
+                    const challenge_len = inner_challenge.salt.length;
-    let target_ptr = Number(target_blob & BigInt(0xFFFFFFFF));
+                    const nonce_ptr = challenge_ptr + challenge_len;
-    let target_len = Number(target_blob >> BigInt(32));
+                    const nonce_len = challenge_buf.length - challenge_len;
 
-    validator.exports.free(salt_ptr, salt_bytes.length);
+                    const target = validator.exports.hash(challenge_ptr, challenge_len, nonce_ptr, nonce_len, algorithmToInt(inner_challenge.algorithm));
-    validator.exports.free(random_number_ptr, random_number_bytes.length);
 
-    // do NOT use `memory` here, by this time it has almost definitely been resized and will cause errors to touch
+                    const target_len = Number((target >> 32n) & 0xFFFFFFFFn);
-    let target_slice = new Uint8Array(validator.exports.memory.buffer.slice(target_ptr, target_ptr + target_len));
+                    const target_ptr = Number(target & 0xFFFFFFFFn);
-    const target = new TextDecoder().decode(target_slice);
 
-    let challenge: ChallengeTargetNumber = {
+                    const target_buf = new Uint8Array(validator.exports.memory.buffer, target_ptr, target_len);
-        algorithm: ChallengeAlgorithm.Argon2id,
+                    // @ts-ignore
-        strategy: ChallengeStrategy.TargetNumber,
+                    inner_challenge.target = new TextDecoder().decode(target_buf);
-        salt,
+                    // @ts-ignore
-        target
+                    console.log("TARGET", inner_challenge.target);
-    };
 
-    return challenge;
+                    validator.exports.free(challenge_ptr, challenge_len + random_number.length);
-}
+                    validator.exports.free(target_ptr, target_len);
-
-export interface LeadingZeroesChallengeConfig {
-    parameters: Object;
-    strategy: ChallengeStrategy.LeadingZeroes;
-    difficulty: number;
-}
-
-export interface TargetNumberChallengeConfig {
-    parameters: Object;
-    strategy: ChallengeStrategy.TargetNumber;
-    max_number: number;
-}
-
-export type ChallengeConfig = LeadingZeroesChallengeConfig | TargetNumberChallengeConfig;
-
-export async function generate_challenge(config: ChallengeConfig): Promise<Challenge | null> {
-    let challenge: Challenge | null = null;
-    switch (config.strategy) {
-        case ChallengeStrategy.LeadingZeroes:
-            challenge = await generate_leading_zeroes_challenge(config.parameters, config.difficulty);
                     break;
-        case ChallengeStrategy.TargetNumber:
+            }
-            challenge = await generate_target_number_challenge(config.parameters, config.max_number);
+            break;
+        case ChallengeAlgorithm.kCTF:
+            if (config.difficulty < 1) {
+                throw new Error("Difficulty must be at least 1");
+            }
+
+            inner_challenge.salt = uuidv7obj();
+            // @ts-ignore
+            inner_challenge.difficulty = config.difficulty;
             break;
     }
 
-    if (challenge === null) {
+    return await encode_challenge(inner_challenge, config.parameters);
-        return null;
 }
 
-    return challenge;
+export async function validate_challenge(challenge: Challenge, challenge_solution: string | number): Promise<boolean> {
+    const validator = (await WebAssembly.instantiateStreaming(fetch(WASMValidatorUrl), {
+        env: {
+            __log: (str_ptr: number, str_len: number) => console.log(new TextDecoder().decode(new Uint8Array(validator.exports.memory.buffer, str_ptr, str_len))),
         }
-
+    })).instance as unknown as ValidatorModule
-export async function validate_challenge(challenge: Challenge, challenge_solution: { challenge: string, nonce: string }): Promise<boolean> {
-    const validator = (await WebAssembly.instantiateStreaming(fetch(WASMValidatorUrl))).instance as unknown as ValidatorModule
-
     const encoder = new TextEncoder();
 
-    let err;
+    if (challenge.algorithm === ChallengeAlgorithm.kCTF) {
-    let memory;
+        challenge.salt = challenge.salt.split("?")[0];
-    let nonce_bytes, nonce_ptr;
+    }
-    let target_bytes, target_ptr;
+
+    const challenge_buf = encoder.encode(challenge.salt);
+    const challenge_ptr = validator.exports.malloc(challenge_buf.length);
+
+    if (challenge_ptr === 0 || challenge_ptr === null) {
+        console.error("Failed to allocate memory for challenge string");
+        return false;
+    }
+
+    const memory = new Uint8Array(validator.exports.memory.buffer);
+    memory.set(challenge_buf, challenge_ptr);
+
+    switch (challenge.algorithm) {
+        case ChallengeAlgorithm.SHA256:
+            if (typeof challenge_solution === "string") {
+                throw new Error("Argon2 challenges do not support a solution as a number");
+            }
+
             switch (challenge.strategy) {
                 case ChallengeStrategy.LeadingZeroes:
-            target_bytes = encoder.encode(challenge_solution.challenge);
+                    return validator.exports.validate(algorithmToInt(challenge.algorithm), strategyToInt(challenge.strategy), challenge_ptr, challenge_buf.length, 0, 0, challenge_solution, challenge.difficulty);
-            nonce_bytes = encoder.encode(challenge_solution.nonce);
-
-            target_ptr = validator.exports.malloc(challenge_solution.challenge.length);
-            nonce_ptr = validator.exports.malloc(challenge_solution.nonce.length);
-
-            if (target_ptr === 0 || target_ptr === null || nonce_ptr === 0 || nonce_ptr === null) {
-                console.error("Failed to allocate memory for challenge string");
-                return false;
-            }
-
-            memory = new Uint8Array(validator.exports.memory.buffer);
-            memory.set(target_bytes, target_ptr);
-            memory.set(nonce_bytes, nonce_ptr);
-
-            err = validator.exports.validate_leading_zeroes_challenge(target_ptr, target_bytes.length, nonce_ptr, nonce_bytes.length, challenge.difficulty);
-
-            validator.exports.free(target_ptr, target_bytes.length);
-            validator.exports.free(nonce_ptr, nonce_bytes.length);
-            break;
                 case ChallengeStrategy.TargetNumber:
-            target_bytes = encoder.encode(challenge.target);
+                    const solution_buf = encoder.encode(challenge.target);
-            const salt_bytes = encoder.encode(challenge.salt);
+                    const solution_ptr = validator.exports.malloc(solution_buf.length);
-            nonce_bytes = encoder.encode(challenge_solution.nonce);
+                    if (solution_ptr === 0 || solution_ptr === null) {
-
-            const salt_ptr = validator.exports.malloc(salt_bytes.length);
-            target_ptr = validator.exports.malloc(target_bytes.length);
-            nonce_ptr = validator.exports.malloc(nonce_bytes.length);
-
-            if (salt_ptr === 0 || salt_ptr === null || target_ptr === 0 || target_ptr === null || nonce_ptr === 0 || nonce_ptr === null) {
                         console.error("Failed to allocate memory for challenge string");
                         return false;
                     }
 
-            memory = new Uint8Array(validator.exports.memory.buffer);
+                    const memory = new Uint8Array(validator.exports.memory.buffer);
-            memory.set(salt_bytes, salt_ptr);
+                    memory.set(solution_buf, solution_ptr);
-            memory.set(target_bytes, target_ptr);
-            memory.set(nonce_bytes, nonce_ptr);
 
-            err = validator.exports.validate_target_number_challenge(target_ptr, target_bytes.length, nonce_ptr, nonce_bytes.length, salt_ptr, salt_bytes.length);
+                    return validator.exports.validate(algorithmToInt(challenge.algorithm), strategyToInt(challenge.strategy), challenge_ptr, challenge_buf.length, solution_ptr, solution_buf.length, challenge_solution, 0);
-
+            }
-            validator.exports.free(salt_ptr, salt_bytes.length);
+        case ChallengeAlgorithm.Argon2:
-            validator.exports.free(target_ptr, target_bytes.length);
+            if (typeof challenge_solution === "string") {
-            validator.exports.free(nonce_ptr, nonce_bytes.length);
+                throw new Error("Argon2 challenges do not support a solution as a number");
-            break;
             }
 
-    return err === 0;
+            switch (challenge.strategy) {
+                case ChallengeStrategy.LeadingZeroes:
+                    return validator.exports.validate(algorithmToInt(challenge.algorithm), strategyToInt(challenge.strategy), challenge_ptr, challenge_buf.length, 0, 0, challenge_solution, challenge.difficulty);
+                case ChallengeStrategy.TargetNumber:
+                    const solution_buf = encoder.encode(challenge.target);
+                    const solution_ptr = validator.exports.malloc(solution_buf.length);
+                    if (solution_ptr === 0 || solution_ptr === null) {
+                        console.error("Failed to allocate memory for challenge string");
+                        return false;
+                    }
+
+                    const memory = new Uint8Array(validator.exports.memory.buffer);
+                    memory.set(solution_buf, solution_ptr);
+
+                    return validator.exports.validate(algorithmToInt(challenge.algorithm), strategyToInt(challenge.strategy), challenge_ptr, challenge_buf.length, solution_ptr, solution_buf.length, challenge_solution, 0);
+            }
+        case ChallengeAlgorithm.kCTF:
+            if (typeof challenge_solution === "number") {
+                throw new Error("KCTF challenges do not support a solution as a number");
+            }
+
+            const solution_buf = encoder.encode(challenge_solution);
+            const solution_ptr = validator.exports.malloc(solution_buf.length);
+            if (solution_ptr === 0 || solution_ptr === null) {
+                console.error("Failed to allocate memory for challenge string");
+                return false;
+            }
+
+            const memory = new Uint8Array(validator.exports.memory.buffer);
+            memory.set(solution_buf, solution_ptr);
+            return validator.exports.validate(algorithmToInt(challenge.algorithm), 0, challenge_ptr, challenge_buf.length, solution_ptr, solution_buf.length, 0, challenge.difficulty);
+    }
 }

packages/lib/vite.config.ts

@@ -18,7 +18,7 @@ export default defineConfig({
                 preserveModules: false
             }
         },
-        minify: true
+        sourcemap: true
     },
     resolve: {
         alias: {

packages/solver/package.json

@@ -1,11 +0,0 @@
-{
-    "name": "solver",
-    "description": "Zig WASM POW solver, not an actual node package, just using this so that pnpm will build it for me",
-    "version": "0.1.0",
-    "private": true,
-    "scripts": {
-        "build": "pnpm run build:wasm && pnpm run minify",
-        "build:wasm": "zig build --release=fast -Dtarget=wasm32-freestanding -Dcpu=generic+bulk_memory+bulk_memory_opt+simd128+tail_call",
-        "minify": "wasm-opt --strip-debug --strip-dwarf -O4 -o zig-out/bin/solver.wasm zig-out/bin/solver.wasm && wasm-opt --strip-debug --strip-dwarf -O4 -o zig-out/bin/validator.wasm zig-out/bin/validator.wasm"
-    }
-}

packages/solver/src/argon2.zig

@@ -1,18 +0,0 @@
-const std = @import("std");
-const Allocator = std.mem.Allocator;
-
-var argon2_params = std.crypto.pwhash.argon2.Params{
-    .t = 3, // time cost
-    .m = 8192, // memory cost (in KiB)
-    .p = 1, // parallelism (this doesnt do anything because we are targeting wasm, and we do multithreading differently anyways)
-};
-
-const dk_len: usize = 32; // 16 or 32 byte key
-var derived: [dk_len]u8 = undefined;
-var buffer_hash_hex: [64]u8 = undefined;
-
-pub fn hash(allocator: Allocator, challenge: []const u8, nonce: []const u8) ![]u8 {
-    try std.crypto.pwhash.argon2.kdf(allocator, &derived, nonce, challenge, argon2_params, .argon2id);
-
-    return derived[0..];
-}

packages/solver/src/solver.zig

@@ -1,155 +0,0 @@
-const std = @import("std");
-const builtin = @import("builtin");
-
-const Allocator = std.mem.Allocator;
-const utils = @import("utils.zig");
-
-const argon2 = @import("argon2.zig");
-
-var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
-var allocator = gpa.allocator();
-
-extern fn __get_solution() i32;
-extern fn __set_solution(value: i32) void;
-extern fn __cmpxchg_solution(old: i32, new: i32) i32;
-extern fn __fetch_add_nonce(value: i32) i32;
-extern fn __log(str_ptr: usize, str_len: usize) void;
-
-fn log(comptime level: std.log.Level, comptime scope: @TypeOf(.EnumLiteral), comptime fmt: []const u8, args: anytype) void {
-    if (comptime builtin.target.cpu.arch != .wasm32) {
-        std.log.defaultLog(level, scope, fmt, args);
-        return;
-    }
-
-    const log_level_str = switch (level) {
-        .err => "Error: ",
-        .warn => "Warning: ",
-        .info => "Info: ",
-        .debug => "Debug: ",
-    };
-
-    const formatted = std.fmt.allocPrint(allocator, fmt, args) catch return;
-    const log_str = std.fmt.allocPrint(allocator, "{s}{s}", .{ log_level_str, formatted }) catch return;
-    allocator.free(formatted);
-    __log(@intFromPtr(log_str.ptr), log_str.len);
-    allocator.free(log_str);
-}
-
-pub const std_options: std.Options = .{ .logFn = log };
-var hex_encoder = utils.HexEncoder{};
-
-export fn malloc(byte_count: usize) ?*u8 {
-    const ptr = allocator.alloc(u8, byte_count) catch return null;
-    return @ptrCast(ptr.ptr);
-}
-
-export fn free(ptr: ?*anyopaque, byte_count: usize) void {
-    if (ptr) |p| {
-        const cast_ptr: [*]u8 = @ptrCast(p);
-        allocator.free(cast_ptr[0..byte_count]);
-    }
-}
-
-// returns nonce on success, -1 on failure
-// to get the error, call get_solve_error
-export fn solve_leaading_zeroes_challenge(challenge_ptr: [*]u8, challenge_len: usize, difficulty: u32) i32 {
-    const challenge_slice = challenge_ptr[0..challenge_len];
-
-    if (difficulty < 1 or difficulty > 64) {
-        std.log.err("Invalid difficulty for leading zeroes\n", .{});
-        return -1;
-    }
-
-    const max_nonce_iterations: u64 = 1_000_000_000;
-
-    // 64 + 9 digits for nonce since the max nonce is 999_999_999 (not 1 billion since nonce < max_nonce_iterations)
-    var input_buffer: []u8 = allocator.alloc(u8, challenge_len + 9) catch {
-        std.log.err("Failed to allocate memory for challenge\n", .{});
-        return -1;
-    };
-    // dont leak memory :pepega:
-    defer allocator.free(input_buffer);
-
-    @memcpy(input_buffer[0..challenge_len], challenge_slice);
-
-    var nonce = __fetch_add_nonce(1);
-
-    while (nonce < max_nonce_iterations) : (nonce = __fetch_add_nonce(1)) {
-        if (__get_solution() != -1) {
-            // solution has already been found, no point in continuing
-            return 0;
-        }
-
-        const nonce_str = std.fmt.bufPrint(input_buffer[challenge_len..], "{d}", .{nonce}) catch {
-            std.log.err("Failed to allocate memory for nonce\n", .{});
-            return -1;
-        };
-
-        const argon2_key = argon2.hash(allocator, input_buffer[0..challenge_len], input_buffer[challenge_len .. challenge_len + nonce_str.len]) catch {
-            std.log.err("Failed to hash argon2 key\n", .{});
-            return -1;
-        };
-
-        _ = hex_encoder.encode(argon2_key);
-        if (!hex_encoder.countZeroes(difficulty)) {
-            continue;
-        }
-
-        // Found a solution!
-        if (__cmpxchg_solution(-1, nonce) == -1) {
-            // we found a solution, and we are the first to do so
-            return nonce;
-        } else {
-            // we found a solution, but we are not the first to do so
-            return 0;
-        }
-    }
-
-    return -1;
-}
-
-export fn solve_target_number_challenge(target_ptr: [*]u8, target_len: usize, salt_ptr: [*]u8, salt_len: usize) i32 {
-    const target_slice = target_ptr[0..target_len];
-    const salt_slice = salt_ptr[0..salt_len];
-
-    // TODO: take in max number
-    const max_nonce_iterations: usize = 1_000_000_000;
-    const max_digits = std.math.log10(max_nonce_iterations);
-
-    var input_buffer: []u8 = allocator.alloc(u8, salt_len + max_digits) catch {
-        return -1;
-    };
-    defer allocator.free(input_buffer);
-
-    @memcpy(input_buffer[0..salt_len], salt_slice);
-
-    var nonce = __fetch_add_nonce(1);
-    while (nonce < max_nonce_iterations) : (nonce = __fetch_add_nonce(1)) {
-        if (__get_solution() != -1) {
-            return 0;
-        }
-
-        const nonce_str = std.fmt.bufPrint(input_buffer[salt_len..], "{d}", .{nonce}) catch {
-            return -1;
-        };
-
-        const argon2_key = argon2.hash(allocator, input_buffer[0..salt_len], input_buffer[salt_len .. salt_len + nonce_str.len]) catch {
-            return -1;
-        };
-
-        const hex_slice = hex_encoder.encode(argon2_key);
-
-        if (std.mem.eql(u8, target_slice, hex_slice)) {
-            // Found a solution!
-            if (__cmpxchg_solution(-1, nonce) == -1) {
-                // we found a solution, and we are the first to do so
-                return nonce;
-            } else {
-                // we found a solution, but we are not the first to do so
-                return 0;
-            }
-        }
-    }
-
-    return -1;
-}

packages/solver/src/validator.zig

@@ -1,76 +0,0 @@
-const std = @import("std");
-const Allocator = std.mem.Allocator;
-
-const argon2 = @import("argon2.zig");
-const utils = @import("utils.zig");
-
-var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
-var allocator = gpa.allocator();
-
-var hex_encoder = utils.HexEncoder{};
-
-export fn malloc(byte_count: usize) ?*u8 {
-    const ptr = allocator.alloc(u8, byte_count) catch return null;
-    return @ptrCast(ptr.ptr);
-}
-
-export fn free(ptr: ?*anyopaque, byte_count: usize) void {
-    if (ptr) |p| {
-        const cast_ptr: [*]u8 = @ptrCast(p);
-        allocator.free(cast_ptr[0..byte_count]);
-    }
-}
-
-export fn validate_leading_zeroes_challenge(challenge_ptr: [*]u8, challenge_len: usize, nonce_ptr: [*]u8, nonce_len: usize, difficulty: u32) i32 {
-    const challenge_slice = challenge_ptr[0..challenge_len];
-    const nonce_slice = nonce_ptr[0..nonce_len];
-
-    if (difficulty < 1 or difficulty > 64) {
-        return -1;
-    }
-
-    const argon2_key = argon2.hash(allocator, challenge_slice, nonce_slice) catch return -2;
-
-    _ = hex_encoder.encode(argon2_key);
-    if (!hex_encoder.countZeroes(difficulty)) {
-        return -3;
-    }
-
-    return 0;
-}
-
-export fn validate_target_number_challenge(target_ptr: [*]u8, target_len: usize, nonce_ptr: [*]u8, nonce_len: usize, salt_ptr: [*]u8, salt_len: usize) i32 {
-    const target_slice = target_ptr[0..target_len];
-    const salt_slice = salt_ptr[0..salt_len];
-    const nonce_slice = nonce_ptr[0..nonce_len];
-
-    const argon2_key = argon2.hash(allocator, salt_slice, nonce_slice) catch return -2;
-    const hex_slice = hex_encoder.encode(argon2_key);
-
-    if (!std.mem.eql(u8, target_slice, hex_slice)) {
-        return -3;
-    }
-
-    return 0;
-}
-
-export fn hash(challenge_ptr: [*]u8, challenge_len: usize, nonce_ptr: [*]u8, nonce_len: usize) u64 {
-    const challenge = challenge_ptr[0..challenge_len];
-    const nonce = nonce_ptr[0..nonce_len];
-    const argon2_key = argon2.hash(allocator, challenge, nonce) catch return 0;
-    const hex_slice = hex_encoder.encode(argon2_key);
-
-    // bs to get the compiler to not whine about hash_slice.len being a u5 annd thus cannot be shifted by 32
-    var ret: u64 = hex_slice.len;
-    ret <<= 32;
-    ret |= @intFromPtr(hex_slice.ptr);
-    return ret;
-}
-
-// pub fn main() void {
-//     const challenge = "4d7220e22a1ea588fea60000ab8874194e4c6ffd71077adbae915826c73dbf48";
-//     const nonce = "4302";
-//     const difficulty = 3;
-
-//     std.log.info("{d}", .{validate_challenge(@constCast(challenge[0..].ptr), challenge.len, @constCast(nonce[0..].ptr), nonce.len, difficulty)});
-// }

packages/widget/package-lock.json

@@ -8,9 +8,6 @@
             "name": "@impost/widget",
             "version": "0.1.0",
             "license": "BSL-1.0",
-            "dependencies": {
-                "comlink": "^4.4.2"
-            },
             "devDependencies": {
                 "@types/node": "^20.11.24",
                 "lit": "^3.1.2",
@@ -1657,11 +1654,6 @@
             "dev": true,
             "license": "MIT"
         },
-        "node_modules/comlink": {
-            "version": "4.4.2",
-            "resolved": "https://registry.npmjs.org/comlink/-/comlink-4.4.2.tgz",
-            "integrity": "sha512-OxGdvBmJuNKSCMO4NTl1L47VRp6xn2wG4F/2hYzB6tiCb709otOxtEYCSvK80PtjODfXXZu8ds+Nw5kVCjqd2g=="
-        },
         "node_modules/compare-versions": {
             "version": "6.1.1",
             "resolved": "https://registry.npmjs.org/compare-versions/-/compare-versions-6.1.1.tgz",

packages/widget/package.json

@@ -23,7 +23,6 @@
         "lit-element": "^3.1.2"
     },
     "devDependencies": {
-        "@impost/lib": "workspace:*",
         "@types/node": "^20.11.24",
         "lit": "^3.1.2",
         "lit-element": "^3.1.2",
@@ -31,7 +30,6 @@
         "tslib": "^2.6.2",
         "typescript": "^5.3.3",
         "vite": "npm:rolldown-vite@latest",
-        "vite-plugin-dts": "^4.5.4",
+        "vite-plugin-dts": "^4.5.4"
-        "comlink": "^4.4.2"
     }
 }

packages/widget/src/captcha.ts

@@ -1,413 +0,0 @@
-import { LitElement, html, css, isServer, type PropertyValues } from 'lit';
-import { customElement, property, state } from 'lit/decorators.js';
-import { type Challenge } from '@impost/lib';
-import { get_wasm_module } from '@impost/lib/solver';
-import * as Comlink from 'comlink';
-
-import SolverWorker from './solver-worker?worker&inline';
-
-type SolverWorkerAPI = Comlink.Remote<typeof import("./solver-worker")>;
-
-@customElement('impost-captcha')
-export class ImpostCaptcha extends LitElement {
-    static override styles = css`
-    :host {
-        display: block;
-        width: var(--impost-widget-width, 250px);
-    }
-    .impost-widget {
-        display: flex;
-        flex-direction: column;
-        border: 1px solid var(--impost-widget-border-color, #505050);
-        font-family: sans-serif;
-        background-color: var(--impost-widget-background-color, #070408);
-        border-radius: var(--impost-widget-border-radius, 8px);
-    }
-    .impost-main {
-        display: flex;
-        align-items: center;
-        gap: 0.375rem;
-        padding: 0.75rem;
-    }
-    .impost-main span {
-        height: min-content;
-    }
-    .impost-checkbox {
-        display: flex;
-        align-items: center;
-        justify-content: center;
-        width: 1.5rem;
-        height: 1.5rem;
-        color: var(--impost-widget-checkbox-color, #6e6e6eff);
-    }
-    .impost-checkbox input {
-        height: 80%;
-        width: 80%;
-        margin: 0;
-    }
-    .impost-footer {
-        display: flex;
-        padding: 0.25rem 0.75rem;
-        font-size: 0.75rem;
-        color: var(--impost-widget-footer-color, #a2a2a2);
-        justify-content: space-around;
-        align-items: end;
-    }
-    .impost-footer div {
-        height: min-content;
-    }
-    .impost-footer #provider-link {
-        margin-left: auto;
-    }
-    .impost-footer div a {
-        color: var(--impost-widget-footer-color, #a2a2a2);
-    }
-    .impost-footer div a:hover {
-        text-decoration: none;
-    }
-  `;
-
-    /// ================================================
-    ///                   Configuration
-    /// ================================================
-
-
-    @property({ type: String })
-    auto: "onload" | "onfocus" | "onsubmit" | "off" = "off";
-
-    @property({ type: String })
-    challengeUrl: string = 'http://localhost:3000/api/pow';
-
-    @property({ type: String })
-    challengejson: string = '';
-
-    @property({ type: Boolean })
-    showHashrate: boolean = false;
-
-    /// ================================================
-    ///                     Internals
-    /// ================================================
-
-    // needed to allow for multiple widgets on the same page if you wanted to
-    // do that for some reason
-    private uid: string = Math.floor(Math.random() * 100000).toString();
-
-    private _internals: ElementInternals | null = null;
-    static formAssociated = true;
-
-    @state()
-    private solution: string | null = null;
-
-    @state()
-    private challengeData: Challenge | null = null;
-
-    @state()
-    private status: 'unsolved' | 'solving' | 'solved' | 'error' = 'unsolved';
-
-    @state()
-    private disabled: boolean = true;
-
-    @state()
-    private hashRate: number = 0;
-
-
-    // stores the nonce and solution atomics
-    private sab: SharedArrayBuffer = new SharedArrayBuffer(8);
-
-    private solverWorkers: SolverWorkerAPI[] | null = null;
-    private nativeWorkers: Worker[] | null = null;
-
-    private solveStartTime: number | null = null;
-    private hashRateInterval: number | null = null;
-
-    override connectedCallback() {
-        super.connectedCallback();
-        this._internals = this.attachInternals();
-        this.fetchChallenge();
-
-        console.log(this._internals.form);
-
-        this.initWorkers();
-
-        switch (this.auto) {
-            case 'onload':
-                this.solveChallenge();
-                break;
-            case 'onfocus':
-                this.addEventListener('focus', () => this.solveChallenge());
-                break;
-            case 'onsubmit':
-                if (this.parentElement?.nodeName === 'FORM') {
-                    this.parentElement.addEventListener('submit', async (ev) => {
-                        if (this.status === 'solved') {
-                            return;
-                        }
-
-                        ev.preventDefault();
-
-                        await this.solveChallenge();
-
-                        const form = this.parentElement as HTMLFormElement;
-
-                        if (form.requestSubmit) {
-                            form.requestSubmit();
-                        } else {
-                            form.submit();
-                        }
-                    });
-                }
-                break;
-        }
-    }
-
-    protected override firstUpdated(_changedProperties: PropertyValues): void {
-        super.firstUpdated(_changedProperties);
-
-        this.disabled = false;
-    }
-
-    override disconnectedCallback() {
-        super.disconnectedCallback();
-        if (this.hashRateInterval !== null) {
-            clearInterval(this.hashRateInterval);
-            this.hashRateInterval = null;
-        }
-
-        for (const worker of this.nativeWorkers || []) {
-            worker.terminate();
-            this.solverWorkers = null;
-            this.nativeWorkers = null;
-        }
-    }
-
-    getCurrentWorkingNonce() {
-        return Atomics.load(new Uint32Array(this.sab), 0);
-    }
-
-    async fetchChallenge() {
-        if (this.challengeData !== null) {
-            return;
-        }
-
-        if (this.challengejson !== '' && this.challengeData === null) {
-            this.challengeData = JSON.parse(this.challengejson);
-            this.challengejson = '';
-            return;
-        }
-
-        // challenge data must be provided by the user when using SSR
-        if (isServer) {
-            return;
-        }
-
-        await fetch(`${this.challengeUrl}/challenge`)
-            .then(response => response.json())
-            .then(data => {
-                this.challengeData = data;
-            })
-            .catch(error => {
-                console.error('Error fetching challenge:', error);
-                this.status = 'error';
-            });
-    }
-
-    async initWorkers() {
-        this.solverWorkers = [];
-        this.nativeWorkers = [];
-
-        const num_workers = navigator.hardwareConcurrency;
-        for (let i = 0; i < num_workers; i++) {
-            const nativeWorker = new SolverWorker();
-            const comlinkWorker = Comlink.wrap<SolverWorkerAPI>(nativeWorker);
-
-            this.nativeWorkers.push(nativeWorker);
-            this.solverWorkers.push(comlinkWorker);
-        }
-
-        const atomics_view = new Int32Array(this.sab);
-        Atomics.store(atomics_view, 0, 0);
-        Atomics.store(atomics_view, 1, 0);
-
-        let wasm_module = await get_wasm_module();
-        let worker_promises: Promise<void>[] = [];
-        for (let i = 0; i < this.solverWorkers.length; i++) {
-            const solver = this.solverWorkers[i]!;
-            worker_promises.push(solver.init(wasm_module, this.sab)); // Direct call to exposed `init` method
-        }
-
-        const timeoutMs = 10 * 1000;
-        let timeout: number;
-        const timeoutPromise = new Promise((_, reject) => {
-            timeout = setTimeout(() => {
-                reject(new Error(`Function timeout after ${timeoutMs}ms`));
-            }, timeoutMs);
-        });
-
-        await Promise.race([
-            Promise.allSettled(worker_promises).then(results => {
-                const failedInits = results.filter(r => r.status === 'rejected');
-                if (failedInits.length > 0) {
-                    console.error('Some workers failed to initialize:', failedInits);
-                    // we might want to collect all errors, and if every 
-                    // worker fails, we can throw, but carry on if only some
-                    // fail. For now, we'll just throw if any fail.
-
-                    throw new Error("One or more workers failed to initialize.");
-                }
-
-                console.log('All workers initialized');
-                return;
-            }),
-            timeoutPromise,
-        ]).then(() => {
-            clearTimeout(timeout);
-        }).catch(error => {
-            clearTimeout(timeout);
-            console.error("Worker initialization failed:", error);
-            this.status = 'error';
-            throw error;
-        });
-    }
-
-    async solveChallenge() {
-        if (!this.challengeData || this.solverWorkers === null) {
-            // in all normal cases, this should be impossible
-            this.status = 'error';
-            return;
-        }
-
-        if (this.solution !== null || this.status !== 'unsolved') {
-            // do not solve twice
-            return;
-        }
-
-        this.solveStartTime = performance.now();
-        this.hashRateInterval = setInterval(async () => {
-            const nonce = this.getCurrentWorkingNonce();
-
-            this.hashRate = (nonce / ((performance.now() - this.solveStartTime!) / 1000));
-            console.log(this.hashRate);
-        }, 250);
-
-        this.dispatchEvent(new CustomEvent('impost:solve', {
-            detail: { challenge: this.challengeData, }, // empty solution
-            bubbles: true,
-            composed: true,
-        }));
-
-        this.status = 'solving';
-        this.solution = null;
-
-        const atomics_view = new Int32Array(this.sab);
-        // reset atomics
-        Atomics.store(atomics_view, 0, 0);
-        Atomics.store(atomics_view, 1, -1);
-
-        console.log('Sending challenge to workers...');
-        // TODO: the first response is not always the solution, due to cmpxchg 
-        // blocking, some workers may block on the read, and as soon as they 
-        // unblock, they return 0 since the challenge is already solved.
-        //
-        // We need to do a better job of tracking solvers, so if one worker
-        // errors out, we only error out if all workers have errored out.
-        let worker_promises: Promise<string>[] = [];
-        for (let solver of this.solverWorkers) {
-            worker_promises.push(solver.solve_challenge(this.challengeData as Challenge));
-        }
-
-        try {
-            await Promise.race(worker_promises);
-
-            // The true solution is stored in the SharedArrayBuffer.
-            this.solution = String(Atomics.load(atomics_view, 1));
-            this.status = 'solved';
-        } catch (error: any) {
-            console.error("Captcha solving failed:", error);
-            this.status = 'error';
-        } finally {
-            if (this.hashRateInterval !== null) {
-                clearInterval(this.hashRateInterval);
-                this.hashRateInterval = null;
-            }
-        }
-
-        if (this.status === 'solved') {
-            this._internals!.setFormValue(JSON.stringify({
-                challenge: this.challengeData.salt,
-                solution: this.solution,
-            }));
-
-            this.dispatchEvent(new CustomEvent('impost:solved', {
-                detail: {
-                    challenge: this.challengeData,
-                    solution: this.solution,
-                },
-                bubbles: true,
-                composed: true,
-            }));
-        }
-    }
-
-    solvePreventDefault(event: Event) {
-        event.preventDefault();
-
-        this.solveChallenge();
-    }
-
-    override render() {
-        if (this.challengejson !== '' && this.challengeData === null) {
-            this.challengeData = JSON.parse(this.challengejson);
-            this.challengejson = '';
-        }
-
-        if (this.challengeData === null) {
-            return html`
-        <div class="loading-message">Loading captcha challenge...</div>
-      `;
-        }
-
-        return html`
-        <div class="impost-widget">
-            <div class="impost-main">
-                <div class="impost-checkbox">
-                    ${this.status !== 'solving' ? html`${this.status === 'error' ? html`<svg class="impost-error-icon" xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 24 24"><!-- Icon from Material Symbols by Google - https://github.com/google/material-design-icons/blob/master/LICENSE --><path fill="currentColor" d="M12 14q-.425 0-.712-.288T11 13V6q0-.425.288-.712T12 5t.713.288T13 6v7q0 .425-.288.713T12 14m0 5q-.425 0-.712-.288T11 18t.288-.712T12 17t.713.288T13 18t-.288.713T12 19"/></svg>` : html`
-                        <input type="checkbox" id="impost-checkbox-${this.uid}" @click=${this.solvePreventDefault} @change=${this.solvePreventDefault} ?disabled=${this.disabled} ?checked=${this.status === 'solved'}>
-                    `}` : html`
-                        <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24">
-                            <!-- Icon from SVG Spinners by Utkarsh Verma - https://github.com/n3r4zzurr0/svg-spinners/blob/main/LICENSE -->
-                            <g stroke="currentColor">
-                                <circle cx="12" cy="12" r="9.5" fill="none" stroke-linecap="round" stroke-width="3">
-                                    <animate attributeName="stroke-dasharray" calcMode="spline" dur="1.5s" keySplines="0.42,0,0.58,1;0.42,0,0.58,1;0.42,0,0.58,1" keyTimes="0;0.475;0.95;1" repeatCount="indefinite" values="0 150;42 150;42 150;42 150"/>
-                                    <animate attributeName="stroke-dashoffset" calcMode="spline" dur="1.5s" keySplines="0.42,0,0.58,1;0.42,0,0.58,1;0.42,0,0.58,1" keyTimes="0;0.475;0.95;1" repeatCount="indefinite" values="0;-16;-59;-59"/>
-                                </circle>
-                                <animateTransform attributeName="transform" dur="2s" repeatCount="indefinite" type="rotate" values="0 12 12;360 12 12"/>
-                            </g>
-                        </svg>
-                    `}
-                </div>
-                <label for="impost-checkbox-${this.uid}">${this.status === 'error' ? 'Something went wrong' : this.status === 'solved' ? 'Verified' : html`${this.status === 'solving' ? 'Verifying...' : 'I am not a robot'}`}</label>
-            </div>
-
-            <div class="impost-footer">
-                ${this.showHashrate && this.status === 'solving' && this.hashRate > 0 ? html`
-                    <div>
-                        <span>H/s:</span>
-                        <span>${this.hashRate.toFixed(2)}</span>
-                    </div>
-                ` : ``}
-                <div id="provider-link">
-                    Protected by <a href="https://github.com/impost/pow-captcha" target="_blank">Impost</a>
-                </div>
-            </div>
-        </div>
-
-        <input
-            type = "text"
-            name = "impost-solution"
-            id = "impost-solution-${this.uid}"
-            style="display: none;"
-            .value = ${this.solution}
-        />
-    `;
-    }
-}

packages/widget/src/entry.ts

@@ -1 +1 @@
-export * from './captcha';
+export * from './pow-captcha';

packages/widget/src/pow-captcha.ts

@@ -0,0 +1,534 @@
+import { LitElement, html, css, isServer, type PropertyValues } from 'lit';
+import { customElement, property, state } from 'lit/decorators.js';
+import { type ChallengeSolveRequest, type SolutionMessage, WorkerMessageType, type WorkerRequest, WorkerResponseType } from './types/worker';
+import { type Challenge, ChallengeStrategy, ChallengeAlgorithm } from '@impost/lib';
+import { get_wasm_module } from '@impost/lib/solver';
+
+import ChallengeWorker from './solver-worker?worker&inline';
+
+@customElement('pow-captcha')
+export class PowCaptcha extends LitElement {
+    static override styles = css`
+    :host {
+        display: block;
+        width: var(--impost-widget-width, 250px);
+    }
+    .impost-widget {
+        display: flex;
+        flex-direction: column;
+        border: 1px solid var(--impost-widget-border-color, #505050);
+        font-family: sans-serif;
+        background-color: var(--impost-widget-background-color, #070408);
+        border-radius: var(--impost-widget-border-radius, 8px);
+    }
+    .impost-error-icon {
+        color: var(--impost-widget-error-icon-color, #FF8117);
+    }
+    .impost-main {
+        display: flex;
+        align-items: center;
+        gap: 0.375rem;
+        padding: 0.75rem;
+    }
+    .impost-main span {
+        height: min-content;
+    }
+    .impost-checkbox {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        width: 1.5rem;
+        height: 1.5rem;
+        color: var(--impost-widget-checkbox-color, #6e6e6eff);
+    }
+    .impost-checkbox input {
+        height: 80%;
+        width: 80%;
+        margin: 0;
+    }
+    .impost-footer {
+        display: flex;
+        padding: 0.25rem 0.75rem;
+        font-size: 0.75rem;
+        color: var(--impost-widget-footer-color, #a2a2a2);
+        justify-content: space-around;
+        align-items: end;
+    }
+    .impost-footer div {
+        height: min-content;
+    }
+    .impost-footer #provider-link {
+        margin-left: auto;
+    }
+    .impost-footer div a {
+        color: var(--impost-widget-footer-color, #a2a2a2);
+    }
+    .impost-footer div a:hover {
+        text-decoration: none;
+    }
+    .hidden {
+        display: none;
+    }
+  `;
+
+
+    // one of: "load", "focus", "submit", "off"
+    @property({ type: String })
+    auto: "onload" | "onfocus" | "onsubmit" | "off" = "off";
+
+    @property({ type: String })
+    challengeUrl: string = 'http://localhost:3000/api/pow';
+
+    @property({ type: String })
+    challengejson: string = '';
+
+    // needed to allow for multiple widgets on the same page if you wanted to
+    // do that for some reason
+    uid: string = Math.floor(Math.random() * 100000).toString();
+
+    @state()
+    private solution: string = '';
+
+    @state()
+    private challengeData: Challenge | null = null;
+
+    @state()
+    private status: 'unsolved' | 'solving' | 'solved' | 'error' = 'unsolved';
+
+    @state()
+    private disabled: boolean = true;
+
+    // stores the nonce and solution atomics
+    private sab: SharedArrayBuffer = new SharedArrayBuffer(8);
+
+    private solverWorkers: Worker[] | null = null;
+
+    override connectedCallback() {
+        super.connectedCallback();
+        this.fetchChallenge();
+
+        this.initWorkers();
+
+        this.addEventListener('reset', (ev) => this.reset(ev as CustomEvent));
+        this.addEventListener('solve', () => this.solveChallenge());
+
+        switch (this.auto) {
+            case 'onload':
+                this.solveChallenge();
+                break;
+            case 'onfocus':
+                this.addEventListener('focus', () => this.solveChallenge());
+                break;
+            case 'onsubmit':
+                if (this.parentElement?.nodeName === 'FORM') {
+                    this.parentElement.addEventListener('submit', () => this.solveChallenge());
+                }
+                break;
+        }
+    }
+
+    protected override firstUpdated(_changedProperties: PropertyValues): void {
+        super.firstUpdated(_changedProperties);
+
+        this.disabled = false;
+    }
+
+    override disconnectedCallback() {
+        super.disconnectedCallback();
+
+        for (const worker of this.solverWorkers || []) {
+            worker.terminate();
+            this.solverWorkers = null;
+        }
+    }
+
+    reset(ev: CustomEvent) {
+        this.challengejson = JSON.stringify(ev.detail.challenge);
+        this.challengeData = null;
+        this.status = 'unsolved';
+        this.solution = '';
+
+        console.log("received reset event");
+
+        this.fetchChallenge();
+
+        console.log(this.challengeData);
+    }
+
+    getCurrentWorkingNonce() {
+        return Atomics.load(new Uint32Array(this.sab), 0);
+    }
+
+    async fetchChallenge() {
+        if (this.challengeData !== null) {
+            return;
+        }
+
+        if (this.challengejson !== '' && this.challengeData === null) {
+            this.challengeData = JSON.parse(this.challengejson);
+            this.challengejson = '';
+            return;
+        }
+
+        if (isServer) {
+            return;
+        }
+
+        await fetch(`${this.challengeUrl}/challenge`)
+            .then(response => response.json())
+            .then(data => {
+                this.challengeData = data;
+            })
+            .catch(error => {
+                console.error('Error fetching challenge:', error);
+                console.error('Failed to fetch challenge');
+            });
+    }
+
+    async initWorkers() {
+        this.solverWorkers = [];
+
+        const num_workers = navigator.hardwareConcurrency || 4;
+        for (let i = 0; i < num_workers; i++) {
+            this.solverWorkers.push(new ChallengeWorker());
+        }
+
+        let wasm_module = await get_wasm_module();
+        let worker_promises: Promise<void>[] = [];
+        for (let i = 0; i < this.solverWorkers.length; i++) {
+            console.log('Worker', i);
+            const worker = this.solverWorkers[i]!;
+
+            worker_promises.push(new Promise<void>((resolve, reject) => {
+                const message_handler = (event: MessageEvent<SolutionMessage>) => {
+                    console.log('Worker', i, 'got message', event.data);
+
+                    if (event.data.type === WorkerResponseType.Error) {
+                        console.error("Worker error:", event.data.error);
+                        reject(event.data.error);
+                    }
+
+                    if (event.data.type === WorkerResponseType.InitOk) {
+                        resolve();
+                    }
+
+                    reject(new Error("Unexpected message from worker"));
+                };
+
+                const error_handler = (error: ErrorEvent) => {
+                    console.error("Worker error:", error);
+                    reject(error);
+                };
+
+                worker.addEventListener('message', message_handler);
+                worker.addEventListener('error', error_handler);
+
+                worker.postMessage({
+                    type: WorkerMessageType.Init,
+                    module: wasm_module,
+                    sab: this.sab,
+                } as WorkerRequest);
+            }));
+        }
+
+        const timeoutMs = 10 * 1000;
+        let timeout: number;
+        const timeoutPromise = new Promise((_, reject) => {
+            timeout = setTimeout(() => {
+                console.error('Failed to initialize workers in time');
+                this.status = 'error';
+                reject(new Error(`Function timed out after ${timeoutMs}ms`));
+            }, timeoutMs);
+        });
+
+        await Promise.race([
+            Promise.allSettled(worker_promises).then(() => {
+                console.log('All workers initialized');
+            }),
+            timeoutPromise,
+        ]).then(() => {
+            clearTimeout(timeout);
+        });
+    }
+
+    async issueChallengeToWorker(worker: Worker, request: ChallengeSolveRequest): Promise<SolutionMessage> {
+        return new Promise<SolutionMessage>((resolve, reject) => {
+            const message_handler = (event: MessageEvent<SolutionMessage>) => {
+                worker.removeEventListener('message', message_handler);
+                worker.removeEventListener('error', error_handler);
+
+                resolve(event.data);
+            };
+
+            const error_handler = (error: ErrorEvent) => {
+                worker.removeEventListener('error', error_handler);
+                worker.removeEventListener('message', message_handler);
+                console.error("Worker error:", error);
+
+                reject(error);
+            };
+
+            worker.addEventListener('message', message_handler);
+            worker.addEventListener('error', error_handler);
+
+            // switch (request.strategy) {
+            //     case ChallengeStrategy.LeadingZeroes:
+            //         worker.postMessage({
+            //             strategy: ChallengeStrategy.LeadingZeroes,
+            //             salt: request.salt,
+            //             difficulty: request.difficulty,
+            //         } as WorkerRequest);
+            //         break;
+            //     case ChallengeStrategy.TargetNumber:
+            //         worker.postMessage({
+            //             strategy: ChallengeStrategy.TargetNumber,
+            //             target: request.target,
+            //             salt: request.salt,
+            //         } as WorkerRequest);
+            //         break;
+            // }
+            switch (request.algorithm) {
+                case ChallengeAlgorithm.SHA256:
+                    switch (request.strategy) {
+                        case ChallengeStrategy.LeadingZeroes:
+                            worker.postMessage({
+                                algorithm: ChallengeAlgorithm.SHA256,
+                                strategy: ChallengeStrategy.LeadingZeroes,
+                                salt: request.salt,
+                                difficulty: request.difficulty,
+                            } as WorkerRequest);
+                            break;
+                        case ChallengeStrategy.TargetNumber:
+                            worker.postMessage({
+                                algorithm: ChallengeAlgorithm.SHA256,
+                                strategy: ChallengeStrategy.TargetNumber,
+                                target: request.target,
+                                salt: request.salt,
+                            } as WorkerRequest);
+                            break;
+                    }
+                    break;
+                case ChallengeAlgorithm.Argon2:
+                    switch (request.strategy) {
+                        case ChallengeStrategy.LeadingZeroes:
+                            worker.postMessage({
+                                algorithm: ChallengeAlgorithm.Argon2,
+                                strategy: ChallengeStrategy.LeadingZeroes,
+                                salt: request.salt,
+                                difficulty: request.difficulty,
+                            } as WorkerRequest);
+                            break;
+                        case ChallengeStrategy.TargetNumber:
+                            worker.postMessage({
+                                algorithm: ChallengeAlgorithm.Argon2,
+                                strategy: ChallengeStrategy.TargetNumber,
+                                target: request.target,
+                                salt: request.salt,
+                            } as WorkerRequest);
+                            break;
+                    }
+                    break;
+                case ChallengeAlgorithm.kCTF:
+                    worker.postMessage({
+                        algorithm: ChallengeAlgorithm.kCTF,
+                        salt: request.salt,
+                        difficulty: request.difficulty,
+                    } as WorkerRequest);
+                    break;
+            }
+        });
+    }
+
+    async solveChallenge() {
+        if (!this.challengeData || this.solverWorkers === null) {
+            console.error('solveChallenge called before challenge is ready');
+            this.status = 'error';
+            return;
+        }
+
+        if (this.solution !== '') {
+            return;
+        }
+
+        this.dispatchEvent(new CustomEvent('impost:solve', {
+            bubbles: true,
+            composed: true,
+        }))
+
+        console.log(this.challengeData);
+
+        this.status = 'solving';
+        this.solution = '';
+
+        const atomics_view = new Int32Array(this.sab);
+        Atomics.store(atomics_view, 0, 0);
+        Atomics.store(atomics_view, 1, -1);
+
+        let request: ChallengeSolveRequest;
+
+        switch (this.challengeData.algorithm) {
+            case ChallengeAlgorithm.SHA256:
+                switch (this.challengeData.strategy) {
+                    case ChallengeStrategy.LeadingZeroes:
+                        request = {
+                            algorithm: ChallengeAlgorithm.SHA256,
+                            strategy: ChallengeStrategy.LeadingZeroes,
+                            salt: this.challengeData.salt,
+                            difficulty: this.challengeData.difficulty,
+                        };
+                        break;
+                    case ChallengeStrategy.TargetNumber:
+                        request = {
+                            algorithm: ChallengeAlgorithm.SHA256,
+                            strategy: ChallengeStrategy.TargetNumber,
+                            target: this.challengeData.target,
+                            salt: this.challengeData.salt,
+                        };
+                        break;
+                }
+                break;
+            case ChallengeAlgorithm.Argon2:
+                switch (this.challengeData.strategy) {
+                    case ChallengeStrategy.LeadingZeroes:
+                        request = {
+                            algorithm: ChallengeAlgorithm.Argon2,
+                            strategy: ChallengeStrategy.LeadingZeroes,
+                            salt: this.challengeData.salt,
+                            difficulty: this.challengeData.difficulty,
+                        };
+                        break;
+                    case ChallengeStrategy.TargetNumber:
+                        request = {
+                            algorithm: ChallengeAlgorithm.Argon2,
+                            strategy: ChallengeStrategy.TargetNumber,
+                            target: this.challengeData.target,
+                            salt: this.challengeData.salt,
+                        };
+                        break;
+                }
+                break;
+            case ChallengeAlgorithm.kCTF:
+                request = {
+                    algorithm: ChallengeAlgorithm.kCTF,
+                    salt: this.challengeData.salt,
+                    difficulty: this.challengeData.difficulty,
+                };
+                break;
+        }
+
+        console.log('Sending challenge to workers...');
+        // TODO: the first response is not always the solution, due to cmpxchg 
+        // blocking, some workers may block on the read, and as soon as they 
+        // unblock, they return 0 since the challenge is already solved.
+        //
+        // TODO: We need to do a better job of tracking solvers, so if one worker
+        // errors out, we only error out if all workers have errored out.
+        let worker_promises: Promise<SolutionMessage>[] = [];
+        if (request.algorithm === ChallengeAlgorithm.kCTF) {
+            worker_promises.push(this.issueChallengeToWorker(this.solverWorkers[0], request));
+        } else {
+            for (let worker of this.solverWorkers) {
+                // dispatch to all workers, func is async so it will not block
+                worker_promises.push(this.issueChallengeToWorker(worker, request));
+            }
+        }
+
+        let solution = await Promise.race(worker_promises);
+
+        if (solution.type === WorkerResponseType.Error) {
+            console.error("Worker error:", solution.error);
+            this.status = 'error';
+            return;
+        }
+
+        if (solution.type !== WorkerResponseType.Solution) {
+            console.error("Worker sent spurious message");
+            this.status = 'error';
+            return;
+        }
+
+        // TODO: configure if we should fetch or not
+        try {
+            await fetch(`${this.challengeUrl}/challenge`, {
+                method: 'POST',
+                body: JSON.stringify({
+                    salt: this.challengeData.salt,
+                    solution: solution.solution,
+                }),
+                headers: {
+                    'Content-Type': 'application/json'
+                }
+            })
+
+            this.status = 'solved';
+
+            this.dispatchEvent(new CustomEvent('impost:solved', {
+                detail: {
+                    salt: this.challengeData.salt,
+                    solution: solution.solution,
+                },
+                bubbles: true,
+                composed: true,
+            }))
+        } catch {
+            console.error('Failed to submit solution');
+            this.status = 'error';
+        }
+    }
+
+    solvePreventDefault(event: Event) {
+        event.preventDefault();
+
+        this.solveChallenge();
+    }
+
+    override render() {
+        if (this.challengejson !== '' && this.challengeData === null) {
+            this.challengeData = JSON.parse(this.challengejson);
+            this.challengejson = '';
+        }
+
+        if (this.challengeData === null) {
+            return html`
+        <div class="loading-message">Loading captcha challenge...</div>
+      `;
+        }
+
+        return html`
+        <div class="impost-widget">
+            <div class="impost-main">
+                <div class="impost-checkbox">
+                    ${this.status !== 'solving' ? html`${this.status === 'error' ? html`<svg class="impost-error-icon" xmlns="http://www.w3.org/2000/svg" width="32" height="32" viewBox="0 0 24 24"><!-- Icon from Material Symbols by Google - https://github.com/google/material-design-icons/blob/master/LICENSE --><path fill="currentColor" d="M12 14q-.425 0-.712-.288T11 13V6q0-.425.288-.712T12 5t.713.288T13 6v7q0 .425-.288.713T12 14m0 5q-.425 0-.712-.288T11 18t.288-.712T12 17t.713.288T13 18t-.288.713T12 19"/></svg>` : html`
+                        <input type="checkbox" id="impost-checkbox-${this.uid}" @click=${this.solvePreventDefault} @change=${this.solvePreventDefault} ?disabled=${this.disabled} ?checked=${this.status === 'solved'}>
+                    `}` : html`
+                        <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24">
+                            <!-- Icon from SVG Spinners by Utkarsh Verma - https://github.com/n3r4zzurr0/svg-spinners/blob/main/LICENSE -->
+                            <g stroke="currentColor">
+                                <circle cx="12" cy="12" r="9.5" fill="none" stroke-linecap="round" stroke-width="3">
+                                    <animate attributeName="stroke-dasharray" calcMode="spline" dur="1.5s" keySplines="0.42,0,0.58,1;0.42,0,0.58,1;0.42,0,0.58,1" keyTimes="0;0.475;0.95;1" repeatCount="indefinite" values="0 150;42 150;42 150;42 150"/>
+                                    <animate attributeName="stroke-dashoffset" calcMode="spline" dur="1.5s" keySplines="0.42,0,0.58,1;0.42,0,0.58,1;0.42,0,0.58,1" keyTimes="0;0.475;0.95;1" repeatCount="indefinite" values="0;-16;-59;-59"/>
+                                </circle>
+                                <animateTransform attributeName="transform" dur="2s" repeatCount="indefinite" type="rotate" values="0 12 12;360 12 12"/>
+                            </g>
+                        </svg>
+                    `}
+                </div>
+                <label for="impost-checkbox-${this.uid}">${this.status === 'error' ? 'Something went wrong' : this.status === 'solved' ? 'Verified' : html`${this.status === 'solving' ? 'Verifying...' : 'I am not a robot'}`}</label>
+            </div>
+
+            <div class="impost-footer">
+                <div id="provider-link">
+                    Protected by <a href="https://github.com/impost/pow-captcha" target="_blank">Impost</a>
+                </div>
+            </div>
+        </div>
+
+        <input
+            type = "text"
+            id = "impost-solution"
+            class="hidden"
+            .value = ${this.solution}
+        />
+    `;
+    }
+}

packages/widget/src/solver-worker.ts

@@ -1,24 +1,26 @@
 // This worker just sits on another thread and waits for message to solve
 // challenges so that we dont block the render thread
 
-import { type Challenge } from "@impost/lib";
+import {
-import { type SolverModule, init_solver, solve_challenge as libimpost_solve_challenge } from '@impost/lib/solver';
+    type WorkerRequest,
-import * as Comlink from 'comlink';
+    type SolutionMessage,
+    WorkerMessageType,
+    WorkerResponseType,
+} from "./types/worker";
+
+import { type SolverModule, init_solver, solve, type SolveParams } from '@impost/lib/solver';
+import { ChallengeStrategy, ChallengeAlgorithm } from '@impost/lib';
 
 let solver: SolverModule | null = null;
 
 let atomic_nonce: Int32Array | null = null;
 let atomic_solution: Int32Array | null = null;
 
-/**
+onmessage = async (event: MessageEvent<WorkerRequest>) => {
- * Initializes the worker.
+    if (event.data.type === WorkerMessageType.Init) {
- * Must be called before any solve functions.
+        atomic_nonce = new Int32Array(event.data.sab, 0, 1);
- * @param module The solver web assembly module.
+        atomic_solution = new Int32Array(event.data.sab, 4, 1);
- * @param sab The SharedArrayBuffer for nonce and solution.
+        let module = event.data.module;
- */
-export async function init(module: WebAssembly.Module, sab: SharedArrayBuffer): Promise<void> {
-    atomic_nonce = new Int32Array(sab, 0, 1);
-    atomic_solution = new Int32Array(sab, 4, 1);
 
         try {
             solver = await init_solver({
@@ -29,36 +31,85 @@ export async function init(module: WebAssembly.Module, sab: SharedArrayBuffer):
                 __log: (str_ptr: number, str_len: number) => console.log(new TextDecoder().decode(new Uint8Array(solver!.exports.memory.buffer, str_ptr, str_len))),
             }, module);
         } catch (error: any) {
-        console.error("Worker: Failed to initialize WASM solver", error);
+            postMessage({
-        throw new Error(`Could not load WASM solver in worker: ${error.message}`);
+                type: WorkerResponseType.Error,
+                error: `Could not load WASM solver: ${error.message}`,
+            } as SolutionMessage);
+            return;
         }
 
         if (!solver) {
-        throw new Error("Worker: Failed to load WASM solver.");
+            postMessage({
-    }
+                type: WorkerResponseType.Error,
+                error: "Failed to load WASM solver",
+            } as SolutionMessage);
+            return;
         }
 
-/**
+        postMessage({
- * Solves a given challenge.
+            type: WorkerResponseType.InitOk,
- * @param challenge The challenge data.
+        } as SolutionMessage);
- * @returns The nonce solution on success, or throws an error.
+        return;
- */
-export async function solve_challenge(challenge: Challenge): Promise<string> {
-    if (!solver || !atomic_nonce || !atomic_solution) {
-        throw new Error("WASM solver or atomics not initialized in worker. Call init() first.");
     }
 
-    console.log("Worker: Solving challenge...");
+    if (!solver) {
-
+        postMessage({
-    const solutionNonce = libimpost_solve_challenge(solver, challenge);
+            type: WorkerResponseType.Error,
-
+            error: "WASM solver not loaded",
-    if (solutionNonce < 0) {
+        } as SolutionMessage);
-        throw new Error(`Worker: Failed to solve challenge. Internal code: ${solutionNonce}`);
+        return;
     }
 
-    const finalSolution = Atomics.load(atomic_solution, 0);
+    let solution: string | number;
-    return finalSolution.toString();
+    try {
+        let params = {
+            name: event.data.algorithm,
+            salt: event.data.salt,
+        };
+
+        switch (event.data.algorithm) {
+            case ChallengeAlgorithm.Argon2:
+            case ChallengeAlgorithm.SHA256:
+                switch (event.data.strategy) {
+                    case ChallengeStrategy.LeadingZeroes:
+                        // @ts-ignore
+                        params.strategy = ChallengeStrategy.LeadingZeroes;
+                        // @ts-ignore
+                        params.difficulty = event.data.difficulty;
+                        break;
+                    case ChallengeStrategy.TargetNumber:
+                        // @ts-ignore
+                        params.strategy = ChallengeStrategy.TargetNumber;
+                        // @ts-ignore
+                        params.target = event.data.target;
+                        break;
+                }
+                break;
+            case ChallengeAlgorithm.kCTF:
+                // @ts-ignore
+                params.strategy = ChallengeStrategy.Null;
+                // @ts-ignore
+                params.difficulty = event.data.difficulty;
+                break;
         }
 
-// * Do not forget to expose functions we want to use on the main thread
+        solution = solve(solver, params as SolveParams);
-Comlink.expose({ solve_challenge, init });
+
+        if (event.data.algorithm !== ChallengeAlgorithm.kCTF) {
+            console.log(Atomics.load(atomic_nonce!, 0));
+            solution = Atomics.load(atomic_solution!, 0);
+        }
+    } catch (error: any) {
+        postMessage({
+            type: WorkerResponseType.Error,
+            error: `Failed to solve challenge: ${error.message}`,
+        } as SolutionMessage);
+        return;
+    }
+
+
+    postMessage({
+        type: WorkerResponseType.Solution,
+        solution,
+    } as SolutionMessage);
+};

packages/widget/src/types/worker.ts

@@ -0,0 +1,72 @@
+import { ChallengeAlgorithm, ChallengeStrategy } from "@impost/lib";
+
+export enum WorkerMessageType {
+    Init = "init",
+    Challenge = "challenge",
+}
+
+interface WorkerInitRequest {
+    type: WorkerMessageType.Init;
+    module: WebAssembly.Module;
+
+    sab: SharedArrayBuffer;
+}
+
+interface ChallengeLeadingZeroesSolveRequest {
+    algorithm: ChallengeAlgorithm.SHA256 | ChallengeAlgorithm.Argon2;
+    strategy: ChallengeStrategy.LeadingZeroes;
+    salt: string;
+    difficulty: number;
+}
+
+interface WorkerChallengeLeadingZeroesSolveRequest extends ChallengeLeadingZeroesSolveRequest {
+    type: WorkerMessageType.Challenge;
+}
+
+interface ChallengeTargetNumberSolveRequest {
+    algorithm: ChallengeAlgorithm.SHA256 | ChallengeAlgorithm.Argon2;
+    strategy: ChallengeStrategy.TargetNumber;
+    target: string;
+    salt: string;
+}
+
+interface WorkerChallengeTargetNumberSolveRequest extends ChallengeTargetNumberSolveRequest {
+    type: WorkerMessageType.Challenge;
+}
+
+interface ChallengekCTFSolveRequest {
+    algorithm: ChallengeAlgorithm.kCTF;
+    salt: string;
+    difficulty: number;
+}
+
+interface WorkerChallengekCTFSolveRequest extends ChallengekCTFSolveRequest {
+    type: WorkerMessageType.Challenge;
+}
+
+export type ChallengeSolveRequest = ChallengekCTFSolveRequest | ChallengeLeadingZeroesSolveRequest | ChallengeTargetNumberSolveRequest;
+type WorkerChallengeSolveRequest = WorkerChallengekCTFSolveRequest | WorkerChallengeLeadingZeroesSolveRequest | WorkerChallengeTargetNumberSolveRequest;
+
+export type WorkerRequest = WorkerInitRequest | WorkerChallengeSolveRequest;
+
+export enum WorkerResponseType {
+    Error = "error",
+    InitOk = "init_ok",
+    Solution = "solution",
+}
+
+interface ErrorMessageResponse {
+    type: WorkerResponseType.Error;
+    error: string;
+}
+
+interface SolutionMessageResponse {
+    type: WorkerResponseType.Solution;
+    solution: string | number;
+}
+
+interface InitOkMessageResponse {
+    type: WorkerResponseType.InitOk;
+}
+
+export type SolutionMessage = ErrorMessageResponse | SolutionMessageResponse | InitOkMessageResponse;

packages/widget/vite.config.ts

@@ -17,10 +17,13 @@ export default defineConfig({
                 dir: 'dist',
             },
         },
-        minify: true
+        // WARN: this setting has caused issues for me in the past, but now it
+        // seems to work fine. I'm not sure why, but minifying the bundle saves
+        // 5KB, and it doesnt *cause* issues, so I'm leaving it on.
+        minify: true,
     },
 
     plugins: [
-        dts()
+        dts(),
     ],
 });

pnpm-workspace.yaml

@@ -1,10 +0,0 @@
-packages:
-  - packages/*
-  - example-app/
-
-onlyBuiltDependencies:
-  - '@parcel/watcher'
-  - core-js-pure
-  - esbuild
-
-shamefully-hoist: true

solver/src/algorithms/algorithms.zig

@@ -0,0 +1,15 @@
+pub const Algorithm = enum(u8) {
+    sha256 = 0,
+    argon2 = 1,
+    kctf = 2,
+};
+
+pub const Strategy = enum(u8) {
+    null = 0,
+    leading_zeros = 1,
+    target_number = 2,
+};
+
+pub const SHA256 = @import("sha256.zig");
+pub const Argon2 = @import("argon2.zig");
+pub const kCTF = @import("kctf.zig");

solver/src/algorithms/argon2.zig

@@ -0,0 +1,17 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+var argon2_params = std.crypto.pwhash.argon2.Params{
+    .t = 3, // time cost
+    .m = 8192, // memory cost (in KiB)
+    .p = 1, // parallelism
+};
+
+const dk_len: usize = 32; // 16 or 32 byte key
+
+pub fn hash(allocator: Allocator, challenge: []const u8, nonce: []const u8) ![]u8 {
+    const derived = try allocator.alloc(u8, dk_len);
+    try std.crypto.pwhash.argon2.kdf(allocator, derived, nonce, challenge, argon2_params, .argon2d);
+
+    return derived;
+}

solver/src/algorithms/kctf.zig

@@ -0,0 +1,155 @@
+// A PoW algorithm based on google's kCTF scheme
+// https://google.github.io/kctf/
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+const assert = std.debug.assert;
+const math = std.math;
+const Int = math.big.int.Managed;
+
+var managed_one: ?Int = null;
+
+fn get_bit(n: *Int, idx: usize) !bool {
+    if (n.len() < idx / @typeInfo(usize).int.bits) {
+        return false;
+    }
+
+    var foo = try n.clone();
+    defer foo.deinit();
+
+    try foo.shiftRight(n, idx);
+    try foo.bitAnd(&foo, &managed_one.?);
+    return foo.eql(managed_one.?);
+}
+
+pub fn square_mod(n: *Int) !void {
+    const allocator = n.allocator;
+    try n.sqr(n);
+
+    var high = try Int.init(allocator);
+    defer high.deinit();
+    try high.shiftRight(n, 1279); // high = n >> 1279
+
+    var mask = try Int.init(allocator);
+    defer mask.deinit();
+
+    if (managed_one == null) {
+        managed_one = try Int.init(allocator);
+        try managed_one.?.set(1);
+    }
+
+    try mask.set(1);
+    try mask.shiftLeft(&mask, 1279);
+    try mask.sub(&mask, &managed_one.?);
+
+    try n.bitAnd(n, &mask);
+
+    try n.add(n, &high);
+
+    if (try get_bit(n, 1279)) {
+        // clear bit 1279
+        var power_of_2 = try Int.init(allocator);
+        defer power_of_2.deinit();
+        try power_of_2.set(1);
+        try power_of_2.shiftLeft(&power_of_2, 1279);
+        try n.sub(n, &power_of_2);
+
+        // *n += 1;
+        try n.add(n, &managed_one.?);
+    }
+}
+
+pub const Challenge = struct {
+    difficulty: usize,
+    salt: std.math.big.int.Managed,
+
+    const Self = @This();
+
+    pub fn destroy(self: *Self, allocator: Allocator) void {
+        self.salt.deinit();
+        allocator.destroy(self);
+    }
+
+    pub fn from_string(allocator: Allocator, challenge: []const u8, difficulty: usize) !*Self {
+        var salt = try std.math.big.int.Managed.init(allocator);
+        errdefer salt.deinit();
+
+        const salt_str = challenge;
+        const salt_bytes_len = try std.base64.standard.Decoder.calcSizeForSlice(salt_str);
+
+        const salt_bytes = try allocator.alloc(u8, salt_bytes_len);
+        defer allocator.free(salt_bytes);
+
+        try std.base64.standard.Decoder.decode(salt_bytes, salt_str);
+
+        const usize_salt_bytes: []align(1) usize = std.mem.bytesAsSlice(usize, salt_bytes);
+        try salt.ensureCapacity(usize_salt_bytes.len);
+        @memcpy(salt.limbs[0..usize_salt_bytes.len], usize_salt_bytes);
+        salt.setLen(usize_salt_bytes.len);
+
+        const challenge_ptr = try allocator.create(Self);
+        errdefer challenge_ptr.destroy(allocator);
+
+        challenge_ptr.* = Self{
+            .difficulty = difficulty,
+            .salt = salt,
+        };
+
+        return challenge_ptr;
+    }
+
+    pub fn encode(self: *Self, allocator: Allocator) ![]u8 {
+        const solution_base64_len = std.base64.standard.Encoder.calcSize(self.salt.len() * @sizeOf(usize));
+        const dest = try allocator.alloc(u8, solution_base64_len);
+        defer allocator.free(dest);
+        @memset(dest, 0);
+
+        const limbs_u8_buffer: []u8 = std.mem.sliceAsBytes(self.salt.limbs[0..self.salt.len()]);
+        const base64_str = std.base64.standard.Encoder.encode(dest, limbs_u8_buffer);
+
+        return try std.fmt.allocPrint(allocator, "{s}", .{base64_str});
+    }
+
+    pub fn solve(self: *Self, allocator: Allocator) ![]u8 {
+        for (0..self.difficulty) |_| {
+            for (0..1277) |_| {
+                try square_mod(&self.salt);
+            }
+            try self.salt.bitXor(&self.salt, &managed_one.?);
+        }
+
+        return try self.encode(allocator);
+    }
+
+    pub fn verify(self: *Self, allocator: Allocator, solution: *Challenge) !bool {
+        if (managed_one == null) {
+            managed_one = try Int.init(allocator);
+            try managed_one.?.set(1);
+        }
+
+        for (0..self.difficulty) |_| {
+            try solution.salt.bitXor(&solution.salt, &managed_one.?);
+
+            try square_mod(&solution.salt);
+        }
+
+        // I'm like 99.999% sure this can NEVER happen, but its how the solution that I translated from did it so that's
+        // how I will do it
+        if (self.salt.eql(solution.salt)) {
+            return true;
+        }
+
+        var foo = try std.math.big.int.Managed.initSet(allocator, 2);
+        defer foo.deinit();
+        try foo.pow(&foo, 1279);
+        try foo.sub(&foo, &managed_one.?);
+        try foo.sub(&foo, &self.salt);
+
+        if (foo.eql(solution.salt)) {
+            std.log.info("challenge solved!\n", .{});
+            return true;
+        }
+
+        return false;
+    }
+};

solver/src/algorithms/sha256.zig

@@ -0,0 +1,9 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+pub fn hash(allocator: Allocator, data: []const u8) ![]u8 {
+    const output_hash = try allocator.alloc(u8, std.crypto.hash.sha2.Sha256.digest_length);
+    std.crypto.hash.sha2.Sha256.hash(data, @ptrCast(output_hash), .{});
+
+    return output_hash;
+}

solver/src/solver.zig

@@ -0,0 +1,291 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const Allocator = std.mem.Allocator;
+
+const algorithms = @import("algorithms/algorithms.zig");
+const utils = @import("utils.zig");
+
+var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
+var allocator = gpa.allocator();
+
+extern fn __get_solution() i32;
+extern fn __set_solution(value: i32) void;
+extern fn __cmpxchg_solution(old: i32, new: i32) i32;
+extern fn __fetch_add_nonce(value: i32) i32;
+extern fn __log(str_ptr: usize, str_len: usize) void;
+
+fn log(comptime level: std.log.Level, comptime scope: @TypeOf(.EnumLiteral), comptime fmt: []const u8, args: anytype) void {
+    if (comptime builtin.target.cpu.arch != .wasm32) {
+        std.log.defaultLog(level, scope, fmt, args);
+        return;
+    }
+
+    const log_level_str = switch (level) {
+        .err => "Error: ",
+        .warn => "Warning: ",
+        .info => "Info: ",
+        .debug => "Debug: ",
+    };
+
+    const formatted = std.fmt.allocPrint(allocator, fmt, args) catch return;
+    const log_str = std.fmt.allocPrint(allocator, "{s}{s}", .{ log_level_str, formatted }) catch return;
+    allocator.free(formatted);
+    __log(@intFromPtr(log_str.ptr), log_str.len);
+    allocator.free(log_str);
+}
+
+pub const std_options: std.Options = .{ .logFn = log };
+
+export fn malloc(byte_count: usize) ?*u8 {
+    const ptr = allocator.alloc(u8, byte_count) catch return null;
+    return @ptrCast(ptr.ptr);
+}
+
+export fn free(ptr: ?*anyopaque, byte_count: usize) void {
+    if (ptr) |p| {
+        const cast_ptr: [*]u8 = @ptrCast(p);
+        allocator.free(cast_ptr[0..byte_count]);
+    }
+}
+
+/// Both SHA256 and Argon2 are thread safe and are explicitly designed to be used in a multithreaded environment.
+/// kCTF is designed only to be used in a single threaded environment. It does not use the same nonce atomics,
+/// and duplicates work if solved across multiple threads.
+///
+/// If a target is not needed for the strategy, target_ptr and target_len should be 0.
+export fn solve(algorithm: algorithms.Algorithm, strategy: algorithms.Strategy, salt_ptr: [*]u8, salt_len: usize, difficulty: usize, target_ptr: [*]u8, target_len: usize) isize {
+    switch (algorithm) {
+        algorithms.Algorithm.sha256 => return solve_argon2_or_sha256(salt_ptr, salt_len, difficulty, algorithm, strategy, target_ptr, target_len),
+        algorithms.Algorithm.argon2 => return solve_argon2_or_sha256(salt_ptr, salt_len, difficulty, algorithm, strategy, target_ptr, target_len),
+        algorithms.Algorithm.kctf => {
+            if (strategy != algorithms.Strategy.null) {
+                std.log.err("kCTF does not support a strategy", .{});
+                return -1;
+            }
+
+            return solve_kctf(salt_ptr, salt_len, difficulty);
+        },
+    }
+}
+
+fn solve_argon2_or_sha256(salt_ptr: [*]u8, salt_len: usize, difficulty: usize, algorithm: algorithms.Algorithm, strategy: algorithms.Strategy, target_ptr: [*]u8, target_len: usize) isize {
+    if (strategy == algorithms.Strategy.null) {
+        std.log.err("Argon2 needs a strategy", .{});
+        return -1;
+    }
+
+    if (strategy == .leading_zeros) {
+        if (difficulty < 1 or difficulty > 64) {
+            std.log.err("Argon2 difficulty must be between 1 and 64 when using leading_zeros", .{});
+            return -1;
+        }
+    }
+
+    const salt_slice = salt_ptr[0..salt_len];
+    var target_slice: ?[]u8 = null;
+    if (@intFromPtr(target_ptr) != 0) {
+        target_slice = target_ptr[0..target_len];
+    }
+
+    if (strategy == .target_number and target_slice == null) {
+        std.log.err("A target must be specified when using the target_number strategy", .{});
+        return -1;
+    }
+
+    const max_nonce_iterations: u64 = 1_000_000_000;
+    // const max_nonce_iterations: u64 = 100_000;
+
+    // 64 + 9 digits for nonce since the max nonce is 999_999_999 (not 1 billion since nonce < max_nonce_iterations)
+    var input_buffer: []u8 = allocator.alloc(u8, salt_len + 9) catch {
+        std.log.err("Out of memory", .{});
+        return -1;
+    };
+    // dont leak memory :pepega:
+    defer allocator.free(input_buffer);
+
+    @memcpy(input_buffer[0..salt_len], salt_slice);
+
+    var nonce = __fetch_add_nonce(1);
+    var hex_encoder = utils.HexEncoder{};
+    var input: []u8 = undefined;
+
+    while (nonce < max_nonce_iterations) : (nonce = __fetch_add_nonce(1)) {
+        if (__get_solution() != -1) {
+            // solution has already been found, no point in continuing
+            return 0;
+        }
+
+        const nonce_str = std.fmt.bufPrint(input_buffer[salt_len..], "{d}", .{nonce}) catch {
+            std.log.err("Error formatting nonce", .{});
+            return -1;
+        };
+
+        if (algorithm == .argon2) {
+            input = algorithms.Argon2.hash(allocator, input_buffer[0..salt_len], input_buffer[salt_len .. salt_len + nonce_str.len]) catch {
+                std.log.err("Error hashing salt", .{});
+                return -1;
+            };
+        } else {
+            input = algorithms.SHA256.hash(allocator, input_buffer[0 .. salt_len + nonce_str.len]) catch {
+                std.log.err("Error hashing salt", .{});
+                return -1;
+            };
+        }
+
+        switch (strategy) {
+            .leading_zeros => {
+                _ = hex_encoder.encode(input);
+                allocator.free(input);
+                if (hex_encoder.countZeroes(difficulty)) {
+                    // Found a solution!
+                    if (__cmpxchg_solution(-1, nonce) == -1) {
+                        // we found a solution, and we are the first to do so
+                        return nonce;
+                    } else {
+                        // we found a solution, but we are not the first to do so
+                        return 0;
+                    }
+                }
+            },
+            .target_number => {
+                const hex = hex_encoder.encode(input);
+                allocator.free(input);
+                if (std.mem.eql(u8, hex, target_slice.?)) {
+                    // Found a solution!
+                    if (__cmpxchg_solution(-1, nonce) == -1) {
+                        // we found a solution, and we are the first to do so
+                        return nonce;
+                    } else {
+                        // we found a solution, but we are not the first to do so
+                        return 0;
+                    }
+                }
+            },
+            else => {
+                std.log.err("Invalid strategy: {s}", .{@tagName(strategy)});
+                return -1;
+            },
+        }
+    }
+
+    return 0;
+}
+
+// value_ptr is a just the base64 challenge string (e.g. "xxxxxxxxx==")
+fn solve_kctf(value_ptr: [*]u8, value_len: usize, difficulty: usize) isize {
+    if (difficulty < 1) {
+        std.log.err("KCTF difficulty must be at least 1", .{});
+        return -1;
+    }
+
+    const challenge_slice = value_ptr[0..value_len];
+
+    const challenge = algorithms.kCTF.Challenge.from_string(allocator, challenge_slice, difficulty) catch |err| {
+        std.log.info("Error decoding challenge: {s}\n", .{@errorName(err)});
+        return -1;
+    };
+    defer challenge.destroy(allocator);
+
+    const solution = challenge.solve(allocator) catch |err| {
+        std.log.info("Error solving challenge: {s}\n", .{@errorName(err)});
+        return -1;
+    };
+
+    const output_ptr = allocator.alloc(u8, solution.len + 4) catch return 0;
+
+    var output_slice = output_ptr[0 .. solution.len + 2];
+    if (output_slice.len - 2 > std.math.maxInt(u16)) {
+        return -1;
+    }
+    const output_len: u16 = @intCast(output_slice.len - 2);
+    // convert to little endian
+    output_slice[0] = @intCast(output_len & 0xFF); // LSB
+    output_slice[1] = @intCast(output_len >> 8); // MSB
+
+    @memcpy(output_slice[2 .. 2 + solution.len], solution);
+    allocator.free(solution);
+
+    return @intCast(@intFromPtr(output_ptr.ptr));
+}
+
+pub fn main() anyerror!void {
+    if (comptime builtin.cpu.arch == .wasm32) return;
+
+    var args = try std.process.argsAlloc(allocator);
+    if (args.len < 2) {
+        std.log.err("Usage: {s} <algorithm> [options] <challenge>", .{args[0]});
+        return;
+    }
+
+    var algorithm: ?algorithms.Algorithm = null;
+    var strategy: algorithms.Strategy = algorithms.Strategy.null;
+    var target: ?[]u8 = null;
+
+    if (std.mem.eql(u8, args[1], "sha256")) {
+        algorithm = algorithms.Algorithm.sha256;
+    } else if (std.mem.eql(u8, args[1], "argon2")) {
+        algorithm = algorithms.Algorithm.argon2;
+    } else if (std.mem.eql(u8, args[1], "kctf")) {
+        algorithm = algorithms.Algorithm.kctf;
+    }
+
+    var i: usize = 2;
+    while (i < args.len) : (i += 1) {
+        const arg = args[i];
+        if (std.mem.eql(u8, arg, "--strategy")) {
+            if (args.len <= i + 1) {
+                std.log.err("Expected strategy after --strategy", .{});
+                return;
+            }
+
+            if (std.mem.eql(u8, args[i + 1], "leading_zeros")) {
+                strategy = algorithms.Strategy.leading_zeros;
+            }
+
+            if (std.mem.eql(u8, args[i + 1], "target_number")) {
+                strategy = algorithms.Strategy.target_number;
+            }
+
+            if (strategy == .null) {
+                std.log.err("Invalid strategy: {s}", .{args[i + 1]});
+                return;
+            }
+
+            i += 1;
+        }
+
+        if (std.mem.eql(u8, arg, "--target")) {
+            if (args.len <= i + 1) {
+                std.log.err("Expected target after --target", .{});
+                return;
+            }
+
+            target = args[i + 1];
+            i += 1;
+        }
+
+        if (std.mem.eql(u8, arg, "--help")) {
+            std.log.info("Options:\n", .{});
+            std.log.info("  --strategy <strategy>: Specify the strategy to use. This only applies to some algorithms.\n", .{});
+            std.log.info("  --target <target>: Specify the target hash when using the target_number strategy.\n", .{});
+            std.log.info("  --help: Print this help message\n", .{});
+            std.log.info("Usage: {s} <strategy> [options] <challenge>", .{args[0]});
+            return;
+        }
+    }
+
+    if (strategy == .null and algorithm != .kctf) {
+        std.log.warn("No strategy specified, defaulting to leading_zeros", .{});
+        strategy = algorithms.Strategy.leading_zeros;
+    }
+
+    if (strategy == .target_number and target == null) {
+        std.log.err("A target must be specified when using the target_number strategy", .{});
+        return;
+    }
+
+    const challenge = try algorithms.kCTF.decode(allocator, args[1]);
+    const solution = try algorithms.kCTF.solve(allocator, challenge);
+
+    std.log.info("Solution: {s}", .{solution});
+}

solver/src/utils.zig

@@ -10,12 +10,7 @@ pub const HexEncoder = struct {
     pub fn encode(self: *Self, bytes: []const u8) []u8 {
         self.scratch_set = true;
 
-        const hex_chars = "0123456789abcdef";
+        bytesToHex(bytes, &self.scratch);
-        var i: usize = 0;
-        while (i < bytes.len) : (i += 1) {
-            self.scratch[i * 2] = hex_chars[(bytes[i] >> 4)];
-            self.scratch[i * 2 + 1] = hex_chars[bytes[i] & 0x0F];
-        }
 
         return &self.scratch;
     }
@@ -41,3 +36,12 @@ pub const HexEncoder = struct {
         return true;
     }
 };
+
+fn bytesToHex(bytes: []const u8, output: []u8) void {
+    const hex_chars = "0123456789abcdef";
+    var i: usize = 0;
+    while (i < bytes.len) : (i += 1) {
+        output[i * 2] = hex_chars[(bytes[i] >> 4)];
+        output[i * 2 + 1] = hex_chars[bytes[i] & 0x0F];
+    }
+}

solver/src/validator.zig

@@ -0,0 +1,177 @@
+const std = @import("std");
+const builtin = @import("builtin");
+const Allocator = std.mem.Allocator;
+
+const algorithms = @import("algorithms/algorithms.zig");
+const utils = @import("utils.zig");
+
+var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
+var allocator = gpa.allocator();
+
+extern fn __log(str_ptr: usize, str_len: usize) void;
+
+fn log(comptime level: std.log.Level, comptime scope: @TypeOf(.EnumLiteral), comptime fmt: []const u8, args: anytype) void {
+    if (comptime builtin.target.cpu.arch != .wasm32) {
+        std.log.defaultLog(level, scope, fmt, args);
+        return;
+    }
+
+    const formatted = std.fmt.allocPrint(allocator, fmt, args) catch return;
+    __log(@intFromPtr(formatted.ptr), formatted.len);
+    allocator.free(formatted);
+}
+
+pub const std_options: std.Options = .{ .logFn = log };
+
+export fn malloc(byte_count: usize) ?*u8 {
+    const ptr = allocator.alloc(u8, byte_count) catch return null;
+    return @ptrCast(ptr.ptr);
+}
+
+export fn free(ptr: ?*anyopaque, byte_count: usize) void {
+    if (ptr) |p| {
+        const cast_ptr: [*]u8 = @ptrCast(p);
+        allocator.free(cast_ptr[0..byte_count]);
+    }
+}
+
+export fn validate(algorithm: algorithms.Algorithm, strategy: algorithms.Strategy, challenge_ptr: [*]u8, challenge_len: usize, solution_ptr: [*]u8, solution_len: usize, nonce: usize, difficulty: usize) bool {
+    switch (algorithm) {
+        algorithms.Algorithm.sha256 => return validate_argon2_or_sha256(challenge_ptr, challenge_len, nonce, solution_ptr, solution_len, difficulty, algorithms.Algorithm.sha256, strategy),
+        algorithms.Algorithm.argon2 => return validate_argon2_or_sha256(challenge_ptr, challenge_len, nonce, solution_ptr, solution_len, difficulty, algorithms.Algorithm.argon2, strategy),
+        algorithms.Algorithm.kctf => return validate_kctf(challenge_ptr, challenge_len, solution_ptr, solution_len, difficulty),
+    }
+}
+
+fn validate_argon2_or_sha256(challenge_ptr: [*]u8, challenge_len: usize, nonce: usize, target_ptr: [*]u8, target_len: usize, difficulty: usize, algorithm: algorithms.Algorithm, strategy: algorithms.Strategy) bool {
+    if (strategy == algorithms.Strategy.null) {
+        return false;
+    }
+
+    if (strategy == .leading_zeros) {
+        if (difficulty < 1 or difficulty > 64) {
+            return false;
+        }
+    }
+
+    const challenge_slice = challenge_ptr[0..challenge_len];
+    const nonce_slice = std.fmt.allocPrint(allocator, "{d}", .{nonce}) catch return false;
+
+    var target_slice: ?[]u8 = null;
+    if (@intFromPtr(target_ptr) != 0) {
+        target_slice = target_ptr[0..target_len];
+    }
+
+    if (strategy == .target_number and target_slice == null) {
+        return false;
+    }
+
+    const input_slice = allocator.alloc(u8, challenge_len + nonce_slice.len) catch return false;
+    defer allocator.free(input_slice);
+    @memcpy(input_slice[0..challenge_len], challenge_slice);
+    @memcpy(input_slice[challenge_len..], nonce_slice);
+
+    var input: []u8 = undefined;
+    if (algorithm == .argon2) {
+        input = algorithms.Argon2.hash(allocator, input_slice[0..challenge_len], input_slice[challenge_len .. challenge_len + nonce_slice.len]) catch return false;
+    } else {
+        input = algorithms.SHA256.hash(allocator, input_slice[0 .. challenge_len + nonce_slice.len]) catch return false;
+    }
+    defer allocator.free(input);
+
+    var hex_encoder = utils.HexEncoder{};
+
+    switch (strategy) {
+        .leading_zeros => {
+            _ = hex_encoder.encode(input);
+            if (hex_encoder.countZeroes(difficulty)) {
+                return true;
+            }
+        },
+        .target_number => {
+            if (std.mem.eql(u8, hex_encoder.encode(input), target_slice.?)) {
+                return true;
+            }
+        },
+        else => unreachable,
+    }
+
+    return false;
+}
+
+fn validate_kctf(challenge_ptr: [*]u8, challenge_len: usize, solution_ptr: [*]u8, solution_len: usize, difficulty: usize) bool {
+    const challenge_buf = challenge_ptr[0..challenge_len];
+    const solution_buf = solution_ptr[0..solution_len];
+
+    const challenge = algorithms.kCTF.Challenge.from_string(allocator, challenge_buf, difficulty) catch return false;
+    const solution = algorithms.kCTF.Challenge.from_string(allocator, solution_buf, difficulty) catch return false;
+    defer {
+        challenge.destroy(allocator);
+        solution.destroy(allocator);
+    }
+
+    const is_valid = challenge.verify(allocator, solution) catch return false;
+
+    return is_valid;
+}
+
+export fn hash(challenge_ptr: [*]u8, challenge_len: usize, nonce_ptr: [*]u8, nonce_len: usize, algorithm: algorithms.Algorithm) u64 {
+    const challenge = challenge_ptr[0..challenge_len];
+    const nonce = nonce_ptr[0..nonce_len];
+
+    var hash_slice: []u8 = undefined;
+    switch (algorithm) {
+        algorithms.Algorithm.sha256 => {
+            const input_slice = allocator.alloc(u8, challenge_len + nonce_len) catch return 0;
+            defer allocator.free(input_slice);
+            @memcpy(input_slice[0..challenge_len], challenge);
+            @memcpy(input_slice[challenge_len..], nonce);
+
+            hash_slice = algorithms.SHA256.hash(allocator, input_slice[0 .. challenge_len + nonce_len]) catch return 0;
+        },
+        algorithms.Algorithm.argon2 => {
+            hash_slice = algorithms.Argon2.hash(allocator, challenge, nonce) catch return 0;
+        },
+        else => return 0,
+    }
+
+    var hex_encoder = utils.HexEncoder{};
+    const hex_slice = hex_encoder.encode(hash_slice);
+    // hex_slice is stack allocated, therefore, if we pass it to the caller without copying it onto the heap, we are
+    // potentially (and likely) sending garbage memory to the caller
+    const heap_hex_slice = allocator.dupe(u8, hex_slice) catch return 0;
+
+    // bs to get the compiler to not whine about hash_slice.len being a u5 annd thus cannot be shifted by 32
+    var ret: u64 = heap_hex_slice.len;
+    ret <<= 32;
+    ret |= @intFromPtr(heap_hex_slice.ptr);
+    allocator.free(hash_slice);
+    return ret;
+}
+
+pub fn main() anyerror!void {
+    // TODO
+    // if (comptime builtin.cpu.arch == .wasm32) return;
+
+    // const args = try std.process.argsAlloc(allocator);
+    // if (args.len < 3) {
+    //     std.log.err("Usage: zig run src/validator.zig <challenge> <solution>", .{});
+    //     return;
+    // }
+
+    // const challenge = try kCTF.decode(allocator, args[1]);
+    // defer challenge.destroy(allocator);
+
+    // const solution = try kCTF.decode(allocator, args[2]);
+    // defer solution.destroy(allocator);
+
+    // std.log.info("Challenge: {any}\n", .{challenge});
+    // std.log.info("Solution: {any}\n", .{solution});
+
+    // const is_valid = kCTF.check(allocator, challenge, solution) catch |err| {
+    //     std.log.info("Error checking challenge: {s}\n", .{@errorName(err)});
+    //     return;
+    // };
+
+    // std.log.info("Is valid: {}\n", .{is_valid});
+}