(PKE, Or "public-Key cryptography") An encryption scheme, introduced by Diffie and Hellman in 1976, where each person gets a pair of Keys, called the public Key and the private Key. Each person' s public Key is published while the private Key is Kept secret. Messages are encrypted using the intended recipient' s public Key and can only be decrypted using his private Key. This is often used in conjunction with a digital signature. The need for sender and receiver to share secret information (Keys) via some secure channel is eliminated: all communications involve only public Keys, and no private Key is ever transmitted or shared. Public-Key encryption can be used for authentication, confidentiality, integrity and non-repudiation. RSA encryption is an example of a public-Key cryptosystem. {alt.security FAQ (http://www.cis.ohio-state.edu/hypertext/faq/bngusenet/alt/security/top.html)}. See also KnapsacK problem. (1995-03-27)