““The Data Encryption Standard (DES) has been by far the most popular block cipher for most of the last 30 years. Even though it is nowadays not considered secure against a determined attacker because the DES key space is too small, it is still used in legacy applications. Furthermore, encrypting data three times in a row with DES — a process referred to as 3DES or triple DES — yields a very secure cipher which is still widely used today””
