Analytics: Ereignisse annehmen

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

analytics/src/salt.js

@@ -0,0 +1,19 @@
+import crypto from 'node:crypto';
+
+const DAY = new Intl.DateTimeFormat('en-CA', { timeZone: 'Europe/Berlin', year: 'numeric', month: '2-digit', day: '2-digit' });
+
+// Tagessalz nur im RAM; neu erzeugt, sobald sich der Kalendertag in Europe/Berlin ändert.
+export function createSalt({ now = Date.now, random = () => crypto.randomBytes(32) } = {}) {
+  let day = null;
+  let salt = null;
+  const current = () => {
+    const d = DAY.format(now());
+    if (d !== day) { day = d; salt = random(); }
+    return salt;
+  };
+  const hmac = (s) => crypto.createHmac('sha256', current()).update(s).digest('hex');
+  return {
+    visitorId: (site, ip, ua) => hmac(`${site}|${ip}|${ua}`).slice(0, 16),
+    rateKey: (site, ip) => hmac(`${site}|${ip}`),
+  };
+}