The DES can also be used for single-user encryption, such as to store files on a hard disk in encrypted form. When used for communication, both sender and receiver must know the same secret key, which can be used to encrypt and decrypt the message, or to generate and verify a Message Authentication Code (MAC). DES is a symmetric cryptosystem, specifically a 16-round Feistel cipher.
These sizes are too small by today’s standards. The DES has a 64-bit block size and uses a 56-bit key during execution (8 parity bits are stripped off from the full 64-bit key). DES was replaced by Triple DES which has itself been superseded by AES.
IBM, the National Security Agency (NSA) and the National Bureau of Standards (NBS now National Institute of Standards and Technology NIST) developed the algorithm. DEA is an improvement of the algorithm Lucifer developed by IBM in the early 1970s. The DEA is also defined in the ANSI standard X3.92. The Data Encryption Standard (DES), is the name of the Federal Information Processing Standard (FIPS) 46-3, which describes the data encryption algorithm (DEA). The DES standard is considered insecure and not recommended for most practical uses.
