PKI
PKI — A system of certificates, trust anchors, policies, and key-management processes used to bind cryptographic public keys to identities.
Cryptographic Context
A public-key infrastructure combines certificate authorities, registration processes, trust anchors, revocation mechanisms such as CRLs or OCSP, and key-protection procedures to bind public keys to identities. TLS and code signing are common applications of this trust model.
Trust Boundary
PKI is not merely a cryptographic algorithm. The security of the system depends at least as much on root-of-trust governance, certificate issuance, renewal, revocation, and private-key protection as on the underlying primitives.