An encryption system in which both the sender and recipient of a message share a single, common key that is used to both encrypt and decrypt the message.

Also called a symmetrical key encryption. With this type of encryption, the same encryption key is used to both encrypt and decrypt a message, and the key is agreed upon and shared by both the sender and receiver

A method of encryption in which the same key is used to encrypt and decrypt. Sometimes referred to as symmetric key cryptography

Encryption process in which both the originator and recipient use the same secret key to encrypt and decrypt data. Also called symmetric key encryption. 12.16 Problem analysis, PDLC, 15.2, 15.4-5

An encryption system that uses two private keys for encrypting and decrypting messages. Both parties must have a secret key to decrypt a message encrypted by the other. The drawback with this method of encryption is in the difficulty of distributing the private keys.