Public key infrastructure and Advanced Message Security

Public key infrastructure (PKI) is a system of facilities, policies, and services that support the use of public key cryptography to obtain secure communication.

There is no single standard that defines the components of a public key infrastructure, but a PKI typically involves usage of public key certificates and comprises certificate authorities (CA) and other registration authorities (RA) that provide the following services:

Issuing digital certificates
Validating digital certificates
Revoking digital certificates
Distributing certificates

Identity of users and applications are represented by the distinguished name (DN) field in a certificate associated with signed or encrypted messages. Advanced Message Security uses this identity to represent a user or an application. To authenticate this identity, the user or application must have access to the keystore where the certificate and associated private key are stored. Each certificate is represented by a label in the keystore.