Triple DES is also known as TDES or , more standard , TDEA ( Triple Data Encryption Algorithm ) . The earliest standard that defines the algorithm ( ANS X9 .52 , published in 1998 ) describes it as the `` Triple Data Encryption Algorithm ( TDEA ) '' -- i.e. three operations of the Data Encryption Algorithm specified in ANSI X3 .92 -- and does not use the terms `` Triple DES '' or `` DES '' at all . FIPS PUB 46-3 ( 1999 ) defines the `` Triple Data Encryption Algorithm ( TDEA ) '' , but also uses the terms `` DES '' and `` Triple DES '' .