(Cryptographic) Registries Considered Harmful
Summary
The author argues that cryptographic registries mapping algorithms or primitives to identifiers often encourage harmful 'cryptographic agility' and introduce protocol vulnerabilities. He advocates fixing primitives per protocol version and avoiding runtime negotiation or registries, using age as a concrete example of a simple, non-registried design. He acknowledges some value in interchangeable primitives but warns registries can cause interoperability and semantic issues, urging version bumps instead of registry-based choices.