# Crypto Agility **Domain:** Cryptography / Resilience / Continuity Infrastructure **Doc Type:** Canonical Security Concept **Maturity:** Current Practice ## Definition **Crypto agility is the capacity to identify, replace and adapt cryptographic algorithms, protocols, keys and implementations while preserving system operations and trust relationships.** ## Continuity Relevance Long-duration custody will outlive current algorithms, certificate authorities, hardware security modules and key holders. Continuity systems need inventories of cryptographic dependencies, versioned trust policies, migration tests, algorithm-independent data structures and the ability to operate old and new mechanisms during controlled transition. Agility is not permission for silent rekeying. Changes to identity-bearing credentials, signatures or recovery authority enter the [[wiki/Digital Thread|Digital Thread]] and require [[wiki/Root of Trust Succession|Root of Trust Succession]]. ## Current Status NIST treats crypto agility as the ability to replace or adapt cryptographic mechanisms while preserving operations. This is an existing cybersecurity practice. Its application to continuity-bearing persons is prospective. ## Sources / Provenance - [NIST CSWP 39: Considerations for Achieving Crypto Agility](https://www.nist.gov/publications/considerations-achieving-crypto-agility-strategies-and-practices). - [NIST Crypto Agility Project](https://csrc.nist.gov/Projects/crypto-agility/publications). ## See Also [[wiki/Cryptographic Succession|Cryptographic Succession]], [[wiki/Post-Quantum Migration|Post-Quantum Migration]], [[wiki/Long-Term Digital Preservation|Long-Term Digital Preservation]]