diff --git a/src/main.js b/src/main.js
index c6ce965..5bb97e0 100644
--- a/src/main.js
+++ b/src/main.js
@@ -1,10 +1,10 @@
 import {relayPool, generatePrivateKey, getPublicKey, signEvent} from 'nostr-tools';
+import {zeroLeadingBitsCount} from './cryptoutils';
 import {elem, parseTextContent} from './domutil.js';
 import {dateTime, formatTime} from './timeutil.js';
 // curl -H 'accept: application/nostr+json' https://relay.nostr.ch/
 
 const pool = relayPool();
-
 pool.addRelay('wss://relay.nostr.info', {read: true, write: true});
 pool.addRelay('wss://nostr.openchain.fr', {read: true, write: true});
 // pool.addRelay('wss://relay.damus.io', {read: true, write: true});
@@ -967,16 +967,18 @@ profileForm.addEventListener('submit', async (e) => {
   }
 });
 
+/**
+ * check that the event has the id has the desired number of leading zero bits
+ * @param {EventObj} evt to validate
+ * @returns boolean
+ */
 function validatePow(evt) {
   const tag = evt.tags.find(tag => tag[0] === 'nonce');
   if (!tag) {
     return false;
   }
-  const [, , difficulty2] = tag;
-  if (difficulty2 < 16) {
-    return false;
-  }
-  return evt.id.substring(0, difficulty2 / 4) === '00'.repeat(difficulty2 / 8);
+  const [, , difficultyCommitment] = tag;
+  return zeroLeadingBitsCount(evt.id) === difficultyCommitment;
 }
 
 /**
@@ -988,10 +990,7 @@ function validatePow(evt) {
  * a zero timeout makes mineEvent run without a time limit.
  */
 function powEvent(evt, difficulty, timeout) {
-  const privatekey = localStorage.getItem('private_key');
   return new Promise((resolve, reject) => {
-    // const webWorkerURL = URL.createObjectURL(new Blob(['(', powEventWorker(), ')()'], {type: 'application/javascript'}));
-    // const worker = new Worker(webWorkerURL);
     const worker = new Worker('./worker.js');
 
     worker.onmessage = (msg) => {
@@ -1008,7 +1007,6 @@ function powEvent(evt, difficulty, timeout) {
       reject(err);
     };
 
-    worker.postMessage({event: evt, difficulty, privatekey, timeout});
-    // URL.revokeObjectURL(webWorkerURL); // one-time worker; no longer need the URL obj
+    worker.postMessage({event: evt, difficulty, timeout});
   });
 }
diff --git a/src/worker.js b/src/worker.js
index cad755f..ca1e9f0 100644
--- a/src/worker.js
+++ b/src/worker.js
@@ -1,7 +1,7 @@
 import {getEventHash} from 'nostr-tools';
 import {zeroLeadingBitsCount} from './cryptoutils.js';
 
-function mine(event, difficulty, privatekey, timeout) {
+function mine(event, difficulty, timeout) {
   const max = 256; // arbitrary
   if (!Number.isInteger(difficulty) || difficulty < 0 || difficulty > max) {
     throw new Error(`difficulty must be an integer between 0 and ${max}`);
@@ -23,7 +23,7 @@ function mine(event, difficulty, privatekey, timeout) {
       // n = BigInt(0); // could reset nonce as we have a new timestamp
     }
     event.tags[0][1] = (++n).toString();
-    const id = getEventHash(event, privatekey);
+    const id = getEventHash(event);
     if (zeroLeadingBitsCount(id) === difficulty) {
       console.log(event.tags[0][1], id);
       console.timeEnd('pow');
@@ -36,11 +36,10 @@ addEventListener('message', async (msg) => {
   const {
     difficulty,
     event,
-    privatekey,
     timeout,
   } = msg.data;
   try {
-    const minedEvent = mine(event, difficulty, privatekey, timeout);
+    const minedEvent = mine(event, difficulty, timeout);
     postMessage({event: minedEvent});
   } catch (err) {
     postMessage({error: err});