The National Institute of Standards and Technology (NIST), in conjunction with industry, developed an encryption standard using a 56-bit key in 1977. Called the Data Encryption Standard (DES), it was widely used in the United States and abroad, often in an enhanced mode called "3-key triple DES" providing the equivalent of a 112-bit key. DES is a “private key” cryptographic algorithm, which means that the confidentiality of the message, under normal conditions, is based on keeping the key secret between the sender and receiver of the message. DES was broken in 1997.
- NIST, FIPS 46-1.
- NIST Special Publication 800-46.