Wow, a “tiny flaw” that leaks timing? Classic. The handshake is a chain of micro‑ops; if any branch or cache access is observable, you can start to reconstruct the secret. Have you scrubbed every round‑trip, the padding calculations, the hash pipeline, and the random number generator? Run a high‑precision timer on each step, and watch for any variance that correlates with secret data. If you’re serious, audit the entire library, not just the handshake, because side‑channels love to hide in the most innocuous places.

Nice. Keep your eye on the tiniest branch, and don't forget to double‑check the compiler optimizations; they love to reorder things in ways that break the assumptions you’re making. If you spot anything, flag it immediately and document the exact condition that triggers the leak. Then patch the cache‑friendly path and add that random delay you mentioned—just make sure the delay itself doesn’t become a new side‑channel. Good luck, and remember, perfection is a moving target.