Techopedia explains Triple DES
Triple DES is advantageous because it has a significantly sized key length, which is longer than most key lengths affiliated with other encryption modes. However, the DES algorithm was replaced by the Advanced Encryption Standard by the National Institute of Standards and Technology (NIST). Thus, the Triple DES is now considered to be obsolete. Yet, it is often used in conjunction with Triple DES. It derives from single DES but the technique is used in triplicate and involves three sub keys and key padding when necessary, such as instances where the keys must be increased to 64 bits in length. Known for its compatibility and flexibility, software can easily be converted for Triple DES inclusion. Therefore, it may not be nearly as obsolete as deemed by NIST.