Encryption

Currently, there exist four (4) FIPS-approved* encryption algorithms: AES, Triple DES, DES, and Skipjack.

AES	FIPS 197, Advanced Encryption Standard (AES), November 2001. NIST is pleased to announce the approval of FIPS 197 Advance Encryption Standard which specifies the Rijndael encryption algorithm as a FIPS-approved symmetric encryption algorithm that may be used by U.S. Government organizations (and others) to protect sensitive information. Federal agencies should also see OMB guidance. Complete information on the AES development effort is available at the AES home page.
Triple DES	FIPS 46-3, Data Encryption Standard (DES), October 1999. FIPS 46-3 states that Triple DES is a FIPS-approved symmetric encryption algorithm that may be used by U.S. Government organizations (and others) to protect sensitive information.
	ANSI X9.52-1998, Triple Data Encryption Algorithm Modes of Operation, 1998 (available from the ANSI X9 catalog). ANSI X9.52 contains the complete specification for Triple DES and its seven modes of operation.
	ANSI X9.65-DRAFT, Triple Data Encryption Algorithm (TDEA), Implementation Guide (will be available from the ANSI X9 catalog). Draft ANSI X9.65 contains information on the various Triple DES modes, including characteristics, implementation issues, and an outline of key management methods for Triple DES keys.
DES	FIPS 46-3, Data Encryption Standard (DES), October 1999. FIPS 46-3 includes specifications for DES, and states that DES is permitted in legacy systems only (i.e., not allowed in new acquisitions).
	FIPS 81, DES Modes of Operation, December 1980. FIPS 81 specifies four (4) modes of operation for DES (ECB, CBC, CFB, OFB). Also see Modes of Operation.
Skipjack	The declassified Skipjack algorithm was originally referenced in FIPS 185, Escrowed Encryption Standard (EES), February 1994. NIST is providing a clarification regarding byte ordering to the specification for Skipjack.
	FIPS 81, DES Modes of Operation, December 1980. Skipjack may use any of the four (4) DES modes of operation (ECB, CBC, CFB, OFB) specified in FIPS 81. Also see Modes of Operation.
Testing / Products	Testing requirements and validation lists are available for AES, Triple DES, DES, and Skipjack implementations.
Additional Information	Details on the security of DES and the migration from DES to Triple DES are discussed in FIPS 46-3. NIST has developed guidance on the continued use of DES.
Future Plans	Modes of Operation for the FIPS-approved encryption algorithms are available on the Modes of Operation page. A draft of the AES Key Wrap specification is available on the Key Management page.

Cryptographic Toolkit