Establish trust using certificates and cryptographic keys.
The certificate, key, and trust services API is a collection of functions and data structures that you use to conduct secure and authenticated data transactions. Specifically, you use this API to manage and use:
Certificates and identities. A certificate is a collection of data that identifies its owner in a tamper-evident way. When you use a certificate to distribute a public key, a receiver can be confident of its origin. You can also package a certificate together with its corresponding private key in an identity object that you keep secret.
Policies and trust services. When you receive a certificate, before you can use the embedded public key, you have to answer the question, “Can I trust this certificate?” You conduct an evaluation of trust according to a set of criteria, or a trust policy.
Cryptographic keys. After you have a key whose origin you trust, you can begin to conduct cryptographic operations, such as encryption or data signing and verification. These operations in turn typically serve a larger purpose, such as authenticating a user, transmitting data securely, or verifying that a block of data is unaltered since being sealed with a signature.