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+# Critical Issue Resolution: security: Implement payload integrity signature validation on client-to-server WebSocket events
+
+## Overview
+Verify packet signatures on the backend for incoming WebSocket payloads to ensure message integrity and prevent tampering during transit.
+
+## Implementation Checklist
+- [x] Write architectural documentation
+- [x] Create components in `backend/middleware/payload_verifier.py`
+- [x] Run verification criteria checks
+
+Closes #552
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