In
cryptography, a
certificate authority or
certification authority (
CA) is an entity that issues
digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon
signatures or on assertions made by the private key that corresponds to the certified public key. In this model of trust relationships, a CA is a
trusted third party—trusted both by the subject (owner) of the certificate and by the party relying upon the certificate. Many
public-key infrastructure (PKI) schemes feature CAs.