A widely-used method of data encryption using a private (secret) key that was judged so difficult to break by the U.S. government that it was restricted for exportation to other countries. There are 72,000,000,000,000,000 (72 quadrillion) or more possible encryption keys that can be used. For each given message, the key is chosen at random from among this enormous number of keys. Like other private key cryptographic methods, both the sender and the receiver must know and use the same private key.
An algorithm for protecting data using private encryption keys. DES-CBC is the Cipher Block Chaining (CBC) mode of DES, a stronger form of encryption, which applies an exclusive OR to each block of data with the previous block and then encrypts the data using the DES encryption key. 3DES or Triple DES is the strongest form of encryption where each data block is encrypted three times with different keys. See also encryption.