Post-Quantum Cryptography

Every blockchain in production today relies on ECDSA or EdDSA. Shor’s algorithm breaks both. This chapter covers the quantum threat model, how Shor’s and Grover’s algorithms hit different layers of the stack, the three NIST post-quantum signature standards (ML-DSA, FN-DSA, SLH-DSA), migration challenges, and why the harvest-now-decrypt-later threat means planning can’t wait. By the end, you’ll understand: