The answer is 3DES
After 1990, the rate of exhaustive key searches against DES began to cause discomfort amongst DES users. Users, however, did not want to replace DES immediately because of the amount of time and money it would take to change encryption which was commonly adopted and used. The approach was not to do away with DES completely, but to change the manner of operation. This led to 3DES. 3DES applies the DES cipher three times consecutively when encrypting data, typically stopping brute-force attacks on modern computers.