diff --git a/js/index.js b/js/index.js
index ed05ab4..9647cda 100644
--- a/js/index.js
+++ b/js/index.js
@@ -3,10 +3,22 @@ import("../pkg/index.js").catch(console.error);
 async function main() {
     const pkg = await import("../pkg/index.js")
     console.log('Downloading previous contribution from /params.bin')
-    let params = await fetch('params.bin')
+    const params = await fetch('params.bin')
     params = new Uint8Array(await params.arrayBuffer())
-    const entropy = new Uint8Array(32)
-    window.crypto.getRandomValues(entropy)
+
+    const userInput = prompt('Please enter some random symbols')
+    if (!userInput.length) {
+        throw new Error('Zero symbols entered')
+    }
+    const msgBuffer = new TextEncoder('utf-8').encode(userInput)
+    const hashBuffer = await window.crypto.subtle.digest('SHA-256', msgBuffer)
+    const entropyFromUser = new Uint8Array(hashBuffer)
+    const entropyFromBrowser = window.crypto.getRandomValues(new Uint8Array(32))
+    const entropy = new Uint8Array(entropyFromBrowser.length)
+    for (let i = 0; i < entropyFromBrowser.length; i++) {
+      entropy[i] = entropyFromBrowser[i] ^ entropyFromUser[i]
+    }
+
     console.log('Contributing with entropy', entropy) // shouldn't be logged on prod
     const result = pkg.contribute(params, entropy)
     console.log('Your contribution', result)