Public key ciphers

For most of the history of cryptography, it was necessary for the key to the encryption system, known to both parties, to be kept secret in order to protect the enciphered data.
Through new methods pioneered in the 1970's that basically changed. Widespread adoption would wait until the advent of the commercial use of the Internet.
RSA and DSA are the most common systems in use here.

For most of the history of cryptography, it was necessary for the key to the encryption system, known to both parties, to be kept secret in order to protect the enciphered data.