1 files changed, 54 insertions, 24 deletions
diff --git a/cmd/anubis/js/proof-of-work.mjs b/cmd/anubis/js/proof-of-work.mjs
index d71d2db..bd69c71 100644
--- a/cmd/anubis/js/proof-of-work.mjs
+++ b/cmd/anubis/js/proof-of-work.mjs
@@ -1,27 +1,35 @@
 // https://dev.to/ratmd/simple-proof-of-work-in-javascript-3kgm
 
-export function process(data, difficulty = 5) {
+export function process(data, difficulty = 5, threads = navigator.hardwareConcurrency) {
   return new Promise((resolve, reject) => {
     let webWorkerURL = URL.createObjectURL(new Blob([
       '(', processTask(), ')()'
     ], { type: 'application/javascript' }));
 
-    let worker = new Worker(webWorkerURL);
+    const workers = [];
 
-    worker.onmessage = (event) => {
-      worker.terminate();
-      resolve(event.data);
-    };
+    for (let i = 0; i < threads; i++) {
+      let worker = new Worker(webWorkerURL);
 
-    worker.onerror = (event) => {
-      worker.terminate();
-      reject();
-    };
+      worker.onmessage = (event) => {
+        workers.forEach(worker => worker.terminate());
+        worker.terminate();
+        resolve(event.data);
+      };
 
-    worker.postMessage({
-      data,
-      difficulty
-    });
+      worker.onerror = (event) => {
+        worker.terminate();
+        reject();
+      };
+
+      worker.postMessage({
+        data,
+        difficulty,
+        nonce: 1000000 * i,
+      });
+
+      workers.push(worker);
+    }
 
     URL.revokeObjectURL(webWorkerURL);
   });
@@ -31,22 +39,44 @@ function processTask() {
   return function () {
     const sha256 = (text) => {
       const encoded = new TextEncoder().encode(text);
-      return crypto.subtle.digest("SHA-256", encoded.buffer).then((result) =>
-        Array.from(new Uint8Array(result))
-          .map((c) => c.toString(16).padStart(2, "0"))
-          .join(""),
-      );
+      return crypto.subtle.digest("SHA-256", encoded.buffer);
     };
 
+    function uint8ArrayToHexString(arr) {
+      return Array.from(arr)
+        .map((c) => c.toString(16).padStart(2, "0"))
+        .join("");
+    }
+
     addEventListener('message', async (event) => {
       let data = event.data.data;
       let difficulty = event.data.difficulty;
-
       let hash;
-      let nonce = 0;
-      do {
-        hash = await sha256(data + nonce++);
-      } while (hash.substring(0, difficulty) !== Array(difficulty + 1).join('0'));
+      let nonce = event.data.nonce || 0;
+
+      while (true) {
+        const currentHash = await sha256(data + nonce++);
+        const thisHash = new Uint8Array(currentHash);
+        let valid = true;
+
+        for (let j = 0; j < difficulty; j++) {
+          const byteIndex = Math.floor(j / 2); // which byte we are looking at
+          const nibbleIndex = j % 2; // which nibble in the byte we are looking at (0 is high, 1 is low)
+
+          let nibble = (thisHash[byteIndex] >> (nibbleIndex === 0 ? 4 : 0)) & 0x0F; // Get the nibble
+
+          if (nibble !== 0) {
+            valid = false;
+            break;
+          }
+        }
+
+        if (valid) {
+          hash = uint8ArrayToHexString(thisHash);
+          console.log(hash);
+          break;
+        }
+      }
 
       nonce -= 1; // last nonce was post-incremented