Software Architect's Handbook

Asymmetric (public key) encryption

Asymmetric encryption, also known as public key encryption, uses two keys to encrypt and decrypt data. One of the keys, called the public key, can be shared with everyone, while the other key, called the private key, is kept secret.

Both keys can be used to encrypt a message and the opposite key from the one used to encrypt a message can be used to decrypt it. For example, a public key can be used for encryption and the private key can be used for decryption. It is generally slower than symmetric encryption/decryption.