Asymmetric-key cryptography (also known as
public-key cryptography) relies on a
key pair to perform both encryption and decryption on the same stream of data. As the name implies, public-key cryptography is what makes a PKI possible (see
Public-Key Infrastructure (PKI)), and it is a much more recent development in cryptography than symmetric (or secret) key cryptography. There are variations on this concept, but the most commonly used algorithms rely on one copy of a key that is owned and kept secret by one entity and multiple copies of a common public key possessed by all other entities that want to communicate with the owner of the private key.
