A Practical Primer on Post-Quantum Cryptography

Most of the encryption protecting the internet today — RSA, ECC, Diffie-Hellman — relies on mathematical problems that classical computers find intractable. Quantum computers, specifically those running Shor's algorithm at scale, will solve these problems efficiently. When that happens, today's encrypted traffic becomes an open book.

The Threat Timeline

The "harvest now, decrypt later" strategy is already in play. Adversaries capture encrypted data today with the expectation that future quantum hardware will let them decrypt it. For data with long confidentiality requirements — government communications, medical records, intellectual property — the threat is present tense, not future.

NIST's Post-Quantum Standards

NIST finalised its first set of post-quantum cryptographic standards in 2024, selecting CRYSTALS-Kyber (now ML-KEM) for key encapsulation and CRYSTALS-Dilithium (ML-DSA) for digital signatures. These are lattice-based schemes — their security depends on the hardness of problems in high-dimensional lattices, which remain difficult for both classical and quantum computers.

What This Means for Builders

If you're designing systems today, the migration to post-quantum algorithms should be on your roadmap. At CronosProof, we're building post-quantum cryptography into the foundation — not as an upgrade path, but as a default. Hardware security modules anchored by atomic clocks and quantum entropy sources ensure that our cryptographic proofs remain valid regardless of how compute evolves.

The transition won't happen overnight, but the organisations that start now will be the ones that don't scramble later.