Data Encryption Standard

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CNSSI 4009

(DES) Cryptographic algorithm, designed for the protection of unclassified data and published by the National Institute of Standards and Technology (NIST) in Federal Information Processing Standard (FIPS) Publication 46. (FIPS 46-3 withdrawn 19 May 2005) (See Triple DES) and CNSS Advisory IA/02-04 Revised March 2005)

NIST SP 800-46

(DES) Data Encryption Standard (DES) is a U.S. Government-approved, symmetric cipher, encryption algorithm used by business and civilian government agencies. The Advanced Encryption Standard (AES) is designed to replace DES. The original "single" DES algorithm is no longer secure because it is now possible to try every possible key with special purpose equipment or a high performance cluster. Triple DES (see glossary entry below), however, is still considered to be secure.

NIST SP 800-48

(DES) A National Institute of Standards and Technology (NIST) standard secret key cryptography method that uses a 56-bit key encryption. DES is based on an IBM algorithm, which was further developed by the U.S. National Security Agency. It uses the block cipher method, which breaks the text into 64-bit blocks before encrypting them. There are several DES encryption modes. The most popular mode exclusive-OR-s each plain-text block with the previous encrypted block. DES decryption is very fast and widely used. The secret key may be kept completely secret and reused again, or a key can be randomly generated for each session, in which case, the new key is transmitted to the recipient using a public key cryptography method such as RSA. Triple DES (3DES) is an enhancement of DES that provides considerably more security than standard DES, which uses only one 56-bit key. There are several 3DES methods. EEE3 uses three keys and encrypts three times. EDE3 uses three keys to encrypt, decrypt, and encrypt again. EEE2 and EDE2 are similar to EEE3 and EDE3, except that only two keys are used, and the first and third operations use the same key.