diff --git a/web/src/app/ConnectionManager.js b/web/src/app/ConnectionManager.js
index 6e5037ce..565cfe9b 100644
--- a/web/src/app/ConnectionManager.js
+++ b/web/src/app/ConnectionManager.js
@@ -1,5 +1,5 @@
 import Connection from "./Connection";
-import {sha256} from "./utils";
+import {hashCode} from "./utils";
 
 /**
  * The connection manager keeps track of active connections (WebSocket connections, see Connection).
@@ -108,10 +108,9 @@ class ConnectionManager {
 }
 
 const makeConnectionId = async (subscription, user) => {
-    const hash = (user)
-        ? await sha256(`${subscription.id}|${user.username}|${user.password}`)
-        : await sha256(`${subscription.id}`);
-    return hash.substring(0, 10);
+    return (user)
+        ? hashCode(`${subscription.id}|${user.username}|${user.password}`)
+        : hashCode(`${subscription.id}`);
 }
 
 const connectionManager = new ConnectionManager();
diff --git a/web/src/app/utils.js b/web/src/app/utils.js
index 5e3644a8..eb440f7f 100644
--- a/web/src/app/utils.js
+++ b/web/src/app/utils.js
@@ -115,10 +115,15 @@ export const shuffle = (arr) => {
     return arr;
 }
 
-// https://jameshfisher.com/2017/10/30/web-cryptography-api-hello-world/
-export const sha256 = async (s) => {
-    const buf = await crypto.subtle.digest("SHA-256", new TextEncoder("utf-8").encode(s));
-    return Array.prototype.map.call(new Uint8Array(buf), x=>(('00'+x.toString(16)).slice(-2))).join('');
+/** Non-cryptographic hash function, see https://stackoverflow.com/a/8831937/1440785 */
+export const hashCode = async (s) => {
+    let hash = 0;
+    for (let i = 0; i < s.length; i++) {
+        const char = s.charCodeAt(i);
+        hash = ((hash<<5)-hash)+char;
+        hash = hash & hash; // Convert to 32bit integer
+    }
+    return hash;
 }
 
 export const formatShortDateTime = (timestamp) => {