In computer and communications security dependent on public key infrastructure (PKI), a certification authority (CA) is an organization, verifiably within that infrastructure, that has the administrative right and technical capablility to issue digital certificates. It may delegate some of its management functions to a registration authority (RA). The CA, however, is the root of all trees of trust for certificates traceable to it.
CAs may serve as a repository of certificates and certificate revocations. CAs may revoke certificates, making them a certificate revocation list issuer.