A data encryption standard developed by IBM under the auspices of the United States Government and adopted as a Federal Standard in 1977. DES uses a 56 bit key to perform a series of nonlinear transformation on a 64 bit data block. Even when it was first introduced a number of years ago, it was criticized for not having a long enough key. 56 bits just didn't put it far enough out of reach of a brute force attack. Today, with the increasing speed of hardware and its falling cost, it would be feasible to build a machine that could crack a 56 bit key in under a day's time. It is not known if such a machine has really been built, but the fact that it is feasible tends to weaken the security of DES substantially. The DES has been rescinded as a Federal Standard. Abbreviation for Data Encryption Standard.