The algorithm specified in FIPS PUB 46-3 –1999, Data Encryption Algorithm.
Sources:
NIST SP 800-20
Triple Data Encryption Algorithm specified in FIPS 46-3
Sources:
NIST SP 800-20
under TDEA
An approved cryptographic algorithm that specifies both the DEA cryptographic engine employed by TDEA and the TDEA algorithm itself.
Sources:
CNSSI 4009-2015