Knowledge Base / Post-Quantum Cryptography
Post-Quantum Cryptography
Public-key cryptography protects almost everything on the internet: web traffic, software updates, VPNs, certificates and signed documents. The algorithms behind it, RSA and elliptic curves, would be broken by a sufficiently large quantum computer. No such computer exists today, but encrypted data can be recorded now and decrypted later, so the migration has to start well before the hardware arrives.
This section explains the standards NIST has published (ML-KEM, ML-DSA and SLH-DSA), the proposed transition timeline, and the practical engineering work: finding where cryptography is used, enabling hybrid key exchange, making systems crypto-agile and planning signature migration. Start with the first three articles in the reading path below if you are new to the topic.
Suggested reading order
- 1Harvest Now, Decrypt Later: The Quantum Threat That Already Applies Today
Why encrypted data captured today can be a liability years from now, how to judge whether your data is at risk, and which mitigations actually reduce exposure.
- 2Demystifying ML-KEM: How NIST's Post-Quantum Key Exchange Works
A plain-language explanation of ML-KEM (FIPS 203): the lattice problem behind it, how key encapsulation works, parameter sets and sizes, and what changes for engineers.
- 3The NIST Post-Quantum Standards Era: What Security Leaders Need to Know
An executive overview of FIPS 203, 204 and 205, the draft NIST IR 8547 transition timeline, and a practical plan for budgeting and governing a cryptographic migration.
- 4Building a Cryptographic Inventory (CBOM): A Practical Method
How to discover and record every place your organization uses cryptography, using code scanning, network discovery and certificate data, and how a CBOM differs from an SBOM.
- 5Step-by-Step Guide: Migrating from RSA and ECDH to ML-KEM
A phased engineering roadmap for moving key exchange from RSA/ECDH to hybrid and then ML-KEM: inventory, prioritization, pilots, rollout, monitoring and rollback.
All Post-Quantum Cryptography articles (8)
- 3 min readBuilding a Cryptographic Inventory (CBOM): A Practical MethodHow to discover and record every place your organization uses cryptography, using code scanning, network discovery and certificate data, and how a CBOM differs from an SBOM.
- 3 min readCrypto-Agility: Design Patterns for Swappable CryptographyConcrete patterns for building systems that can change algorithms without rewrites: abstraction layers, algorithm identifiers, versioned envelopes, dual-write rotation and policy as configuration.
- 3 min readHarvest Now, Decrypt Later: The Quantum Threat That Already Applies TodayWhy encrypted data captured today can be a liability years from now, how to judge whether your data is at risk, and which mitigations actually reduce exposure.
- 3 min readHybrid TLS in Practice: X25519MLKEM768 ExplainedHow hybrid post-quantum key exchange works in TLS 1.3, why X25519MLKEM768 became the default, what it costs in bytes, and how to enable and verify it.
- 3 min readPost-Quantum Digital Signatures: ML-DSA and SLH-DSA ComparedHow FIPS 204 (ML-DSA) and FIPS 205 (SLH-DSA) differ, their key and signature sizes, where signatures matter most (code signing, PKI, firmware), and how to plan migration.
- 4 min readDemystifying ML-KEM: How NIST's Post-Quantum Key Exchange WorksA plain-language explanation of ML-KEM (FIPS 203): the lattice problem behind it, how key encapsulation works, parameter sets and sizes, and what changes for engineers.
- 3 min readStep-by-Step Guide: Migrating from RSA and ECDH to ML-KEMA phased engineering roadmap for moving key exchange from RSA/ECDH to hybrid and then ML-KEM: inventory, prioritization, pilots, rollout, monitoring and rollback.
- 3 min readThe NIST Post-Quantum Standards Era: What Security Leaders Need to KnowAn executive overview of FIPS 203, 204 and 205, the draft NIST IR 8547 transition timeline, and a practical plan for budgeting and governing a cryptographic migration.