solver: add seeded challenges support

docs/.vitepress/config.mjs

@@ -158,8 +158,7 @@ export default withMermaid({
         items: [
           { text: "Server", link: "/guide/server.md" },
           { text: "Widget", link: "/guide/widget.md" },
-          { text: "Solver", link: "/guide/solver.md" },
-          { text: "CLI", link: "/guide/cli.md" },
+          { text: "Solver", link: "/guide/solver.md" }
         ],
       },
       {

docs/guide/solver.md

@@ -1,6 +1,6 @@
 # @cap.js/solver
 
-`@cap.js/solver` is a standalone library that can be used to solve Cap challenges from the server. It's extremely simple (no dependencies, one single file) yet very fast and efficient. Note that it can only be used with Bun.
+`@cap.js/solver` is a standalone library that can be used to solve Cap challenges from the server. It's extremely simple (no dependencies, one single file) yet as fast and efficient as the widget. Note that it can **only be used with Bun**. Node.js support is not planned.
 
 ## Installation
 
@@ -10,10 +10,26 @@ bun add @cap.js/solver
 
 ## Usage
 
+#### From seeded challenges
+
 ```js
 import solver from "@cap.js/solver";
 
-const CHALLENGES = [
+console.log(
+  await solver("challenge token", {
+    c: 50, // challenge count
+    s: 32, // salt size
+    d: 4, // difficulty
+  })
+);
+```
+
+#### From challenge list
+
+```js
+import solver from "@cap.js/solver";
+
+const challenges = [
   ["a5b6fda4aaed97cf61d7dd9259f733b5", "d455"],
   ["286bcc39249f9ee698314b600c32e40f", "f0ff"],
   ["501350aa7c46573cb604284554045703", "4971"],
@@ -22,26 +38,29 @@ const CHALLENGES = [
   /* ... */
 ];
 
-console.log(await solver(CHALLENGES));
+console.log(await solver(challenges));
 ```
 
 **Output:**
 
 ```json
-[
-  ["a5b6fda4aaed97cf61d7dd9259f733b5", "d455", 67302],
-  ["286bcc39249f9ee698314b600c32e40f", "f0ff", 64511],
-  ["501350aa7c46573cb604284554045703", "4971", 40440],
-  ["a55c02f3b9b4cd088a5a7ee3d4941c14", "eab7", 27959],
-  ["5f3362c12e2779f56f4ef75b4494f5e6", "999f", 71259],
-  ...
-]
+[67302, 64511, 40440, 27959, 71259 /* ... */]
 ```
 
+The 2nd argument is optional but can always be provided. It's always an object.
+
+- For **all challenge types**, `workerCount` indicates the number of workers to use (default is the number of CPU cores).
+
+- For **all challenge types**, `onProgress` can also be used to provide a callback for progress updates.
+
+- For **seeded challenges only**, it is used to specify the number of solutions to generate, the size of the challenges, and the difficulty
+
 ## FAQ
 
 ### Why is this needed?
+
 Mainly for M2M interactions, where you want to solve Cap challenges on the server without user interaction.
 
 ### Doesn't this defeat the purpose of Cap?
-Not really. Server-side solving is a core use case of proof-of-work CAPTCHAs like Cap or altcha. It's about proving effort, not necessarily involving a human. [Learn more](./effectiveness.md)
+
+Not really. Server-side solving is a core use case of proof-of-work CAPTCHAs like Cap or altcha. It's about proving effort, not necessarily involving a human. [Learn more](./effectiveness.md)

solver/example/list.js

@@ -1,4 +1,4 @@
-import solver from "./index.js";
+import solver from "../index.js";
 
 const CHALLENGES = [
   ["e455cea65e98bc3c36287f43769da211", "dceb"],

solver/example/seeded.js

@@ -0,0 +1,19 @@
+import solver from "../index.js";
+
+const timeStart = new Date().getTime();
+const solutions = await solver(Math.random().toString(), {
+  onProgress: (status) => {
+    process.stdout.moveCursor(0, -1);
+    process.stdout.clearScreenDown();
+    console.log(`Progress: ${status.progress}%`);
+  },
+  c: 50,
+  s: 30,
+  d: 4,
+});
+
+process.stdout.moveCursor(0, -1);
+process.stdout.clearScreenDown();
+
+console.log("Solutions:", solutions);
+console.log("Time taken:", ((new Date().getTime()) - timeStart).toFixed(2), "ms");

solver/index.js

@@ -1,6 +1,34 @@
 import { Worker } from "worker_threads";
 import os from "os";
-import { performance } from "perf_hooks";
+
+function prng(seed, length) {
+  function fnv1a(str) {
+    let hash = 2166136261;
+    for (let i = 0; i < str.length; i++) {
+      hash ^= str.charCodeAt(i);
+      hash +=
+        (hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) + (hash << 24);
+    }
+    return hash >>> 0;
+  }
+
+  let state = fnv1a(seed);
+  let result = "";
+
+  function next() {
+    state ^= state << 13;
+    state ^= state >>> 17;
+    state ^= state << 5;
+    return state >>> 0;
+  }
+
+  while (result.length < length) {
+    const rnd = next();
+    result += rnd.toString(16).padStart(8, "0");
+  }
+
+  return result.substring(0, length);
+}
 
 const workerBlob = new Blob(
   [
@@ -18,8 +46,6 @@ try {
   
   parentPort.postMessage({
     nonce,
-    salt,
-    target,
     challengeIndex,
     duration
   });
@@ -40,7 +66,22 @@ try {
 
 const workerUrl = URL.createObjectURL(workerBlob);
 
-export default function wasmSolver(challenges, config = {}) {
+export default function solve(challenge, config = {}) {
+  let challenges = challenge;
+
+  if (!Array.isArray(challenges)) {
+    let i = 0;
+
+    challenges = Array.from({ length: config.c }, () => {
+      i = i + 1;
+
+      return [
+        prng(`${challenges}${i}`, config.s),
+        prng(`${challenges}${i}d`, config.d),
+      ];
+    });
+  }
+
   const totalChallenges = challenges.length;
   const numWorkers =
     config?.workerCount || Math.min(totalChallenges, os.cpus().length);
@@ -50,9 +91,11 @@ export default function wasmSolver(challenges, config = {}) {
   let activeWorkers = 0;
   const results = new Array(totalChallenges);
 
-  return new Promise((resolve, reject) => {
-    const startTime = performance.now();
+  if (totalChallenges === 0) {
+    resolve([]);
+  }
 
+  return new Promise((resolve, reject) => {
     function startWorker() {
       if (nextChallengeIndex < totalChallenges && activeWorkers < numWorkers) {
         const currentChallengeIndex = nextChallengeIndex;
@@ -77,11 +120,7 @@ export default function wasmSolver(challenges, config = {}) {
             return;
           }
 
-          results[result.challengeIndex] = [
-            result.salt,
-            result.target,
-            result.nonce,
-          ];
+          results[result.challengeIndex] = result.nonce;
           challengesProcessed++;
 
           if (config?.onProgress) {
@@ -97,10 +136,10 @@ export default function wasmSolver(challenges, config = {}) {
           }
 
           if (challengesProcessed === totalChallenges) {
-            resolve(results.filter(Boolean));
-          } else {
-            startWorker();
+            return resolve(results);
           }
+
+          startWorker();
         });
 
         worker.on("error", (err) => {
@@ -115,9 +154,5 @@ export default function wasmSolver(challenges, config = {}) {
     for (let i = 0; i < numWorkers; i++) {
       startWorker();
     }
-
-    if (totalChallenges === 0) {
-      resolve([]);
-    }
   });
 }

solver/package.json

@@ -1,11 +1,11 @@
 {
   "name": "@cap.js/solver",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "description": "Server-side solver for Cap, a lightweight, modern open-source CAPTCHA alternative designed using SHA-256 PoW.",
   "main": "index.js",
   "scripts": {
     "test": "bun ./example.js",
-    "npm:publish": "npm publish --access public"
+    "npm:publish": "bun publish --access public"
   },
   "author": "Tiago",
   "license": "Apache-2.0",