## Asymmetric, or Public Key, Cryptography

Public-key cryptography is also called asymmetric. It uses a
secret key that must be kept from unauthorized users and a
public key that can be made public to anyone. Both the public
key and the private key are mathematically linked; data
encrypted with the public key can be decrypted only by the
private key, and data signed with the private key can only be
verified with the public key.

The public key can be published to anyone. Both keys are unique
to the communication session.

Public-key cryptographic algorithms use a fixed buffer size.
Private-key cryptographic algorithms use a variable length
buffer. Public-key algorithms cannot be used to chain data
together into streams like private-key algorithms can. With
private-key algorithms only a small block size can be processed,
typically 8 or 16 bytes.