Post-quantum cryptography

Post-quantum cryptography (PQC) refers to a set of cryptographic algorithms that are believed to be secure against both classical and quantum computers. The urgency comes from the threat that a sufficiently powerful quantum computer could break RSA and elliptic curve cryptography (ECC) by running Shor’s algorithm, which solves the integer factorization and discrete logarithm problems that underpin those systems. NIST finalized its first set of post-quantum standards in 2024: ML-KEM (formerly CRYSTALS-Kyber) for key encapsulation and ML-DSA (formerly CRYSTALS-Dilithium) for digital signatures.

The practical migration challenge is that cryptography is embedded in almost every protocol and system: TLS, SSH, code signing, PKI, VPNs, and hardware security modules. Organizations that have not inventoried where and how they use public-key cryptography cannot plan a transition. “Harvest now, decrypt later” attacks make the timeline tighter than it appears: adversaries collecting encrypted traffic today can decrypt it once quantum hardware matures. Long-lived sensitive data (government secrets, medical records, intellectual property with decade-scale value) is already at risk if it was transmitted under classical algorithms.