CyberStor gloss for non-cybersecurity specialists DES An abbreviation of "Data Encryption Standard", a popular symmetric-key encryption method standardized by the American National Standards Institute in 1981 as ANSI X.3.92. DES uses a 56-bit key together with the block cipher method, which breaks text into 64-bit blocks that are then encrypted individually. Triple DES Also referred to as 3DES. A mode of the DES encryption algorithm that encrypts data three times. Three 64-bit keys are used, instead of one, for a total key length of 192 bits. The first encryption is encrypted with a second key, and the resulting cipher text is encrypted again with a third key.