One of the most common questions I've gotten on my posts is - "won't traditional banking break before Bitcoin?" the answer is yes, if they don't change before Q-Day. That's still not a reason to do nothing now IMHO.
🚨 High Risk (Breaks Fast): DH (Key Exchange): Used in SSL/TLS, industrial systems. Vulnerable to "Shor’s algorithm." RSA-1024/2048: Found in banking, SSL/TLS, and SSH. Will fall quickly to quantum attacks.
⚠️ Moderate to High Risk: ECDH-256: Secures IoT, SSH, SSL/TLS. Quantum attacks will compromise it. ECDSA-256: Secures Bitcoin, Signal, banking. Same vulnerability as ECDH.
🛡️ Lower Risk: AES-128: Moderate risk; Grover’s algorithm halves its security to 2^{64}. SHA-256: Low risk; remains strong even after quantum optimization. AES-256: Very low risk, with effective security still at 2^{128}.
âś… Post-Quantum Resilient (Safe for Now): Lattice-Based, Hash-Based (Merkle), Code-Based (McEliece): Emerging systems designed to withstand both classical and quantum attacks.