A very popular encryption method that uses two keys: a public key and a private key. When a message is sent to a person who is the only one entitled to view it, the sender uses the recipient's public key to encrypt the message. The recipients use their private (secret) keys to decrypt the message.
With digital signatures, the sender's private key is used to encrypt a digest of the message, and the sender's public key is used to decrypt it. Contrast with symmetric cryptography
, which uses the same key at both ends. See public key cryptography
, digital signature