Definition
Public key infrastructure (PKI)
The underlying system of digital keys and certificates that makes digital signatures trustworthy.
In Depth
PKI is the plumbing behind the scenes. Each person gets a pair of keys, one public and one private, and a network of trusted organizations issues digital certificates that tie a key to a real identity. This is what lets a stranger confirm that a signature genuinely belongs to you. It handles the whole life cycle too, issuing certificates, maintaining them, and revoking them when needed.
Consistent across the US, UK and EU. PKI is a global technical standard, so the concept does not vary. The EU and UK add a legal layer on top through eIDAS, which regulates the "trust service providers" that run this infrastructure.
Sources
- NIST Computer Security Resource Center Glossary - A set of policies, processes, server platforms, software and workstations used for the purpose of administering certificates and public-private key pairs, including the ability to issue, maintain, and revoke public key certificates. Official Guidance csrc.nist.gov/glossary/term/public_key_infrastructure