data encryption standard (DES)
The Data Encryption Standard(DES) is a cryptographic algorithm developed by the U.S. National Bureau of Standards ( NBS), i.e., a closed-form encryption computation with a cyclically repeating regularity for the encryption and decryption ofdata.
The DES algorithm was developed in the 1970s by IBM for the National Bureau of Standard and uses a 64-bit key that allows combinations of substitution ciphers, transposition ciphers, and exclusive-or functions(XORing). The 64-bit data set consists of an effective key length of 56 bits and 8 parity bits, and the underlying encryption scheme is called Lucifer. DES encryption has been supplemented by an improved triple DES version( 3DES).
The Data Encryption Standard, the best known and most proven symmetric encryption, was published in 1974 and standardized in the USA as an ANSI standard(ANSI X3.92-1981); it is also specified by the International Standards Organization( ISO) under ISO 8227. It has been used for many years, particularly for the transmission of sensitive data, such as that found in capital markets and on smart cards, and can be described as an international quasi-standard.
The DES standard was replaced in 2001 by an improved procedure, the Advanced Encryption Standard( AES).