What are public and private keys, and what is their relationship?
A PKI uses asymmetric cryptography to encrypt and decrypt information. In asymmetric cryptography, encryption is done by a freely available public key, and decryption is done by a closely guarded private key. Although the public and private keys in a particular key pair are mathematically related, it is impossible to determine one key from the other. Each key in an asymmetric key pair performs a function that only the other can undo.