Certificate Authorities (CA) are the central authority who are responsible gor the creation and management of certificates. CA consists of software and hardware components as welle as the people who operate the system. A CA differs from another in its name and key pair (public and private).

The duties of the CAs are as follows:

• Issuing and publisghing certificates
• Keeping certificate status date up-to-date and publishing CRLs
• Keeping archive of revoked and expierd certificates

The one important component of PKI systems is the user of the certificates. They request certificates from certificate authorites.Users get equipped with services like creating signatures, key agreement and authentication by having certificates.

Certificate Users:

• Trusts the CAs issuing their certificates
• Can verify their signatures and authenticate their identities.
• Can reach the certificate of anyone they wish to contact with.