[Originally published as Federal Standard 1027 (FED-STD-1027) by the General Services Administration. Note on Cover: "Federal Standard 1027 has been redesignated as Federal Information Processing Standards Publication (FIPS PUB) 140." Per Federal Register Notice FR 53 41221, October 20, 1988.]

This standard specifies the minimum general security requirements that are to be satisfied in implementing the Data Encryption Standard (DES) algorithm in a telecommunications environment. The DES itself specifies an algorithm used for cryptographically protecting certain U.S. Government information. (This algorithm is described in Federal Information Processing Standards Publication 46). The requirements defined in this standard affect the security of equipment implementing the DES algorithm. Other security requirements, which relate to the interface and interoperability of DES cryptographic equipment with associated terminal equipment (e.g., narrative text, automatic data processing, digital facsimile, digital voice, etc.), will be addressed in other Federal telecommunication standards.