Since its invention, security of DES has been studied intensively. Special techniques such as differential cryptanalysis and linear cryptanalysis have been invented to attack DES (e.g. reducing key space from to ).
Most successful attack is an exhaustive search of the key space.
- Special hardware or large networks of workstations can decrypt DES ciphertexts in a few days or even a few hours. hours with million dollar computer in 1993.
- DES will be breakable on a single PC.