Reducing the exhaustive key search of the Data Encryption Standard (DES)

The Data Encryption Standard (DES) is among the most popular encryption method that has become the de facto standard to protect confidential information ranging from Automatic Teller Machines (ATMs) and smart cards to emails and online websites. Although recently a successor — the Advanced Encryption Standard (AES) has emerged, DES and its variants remain being used in various applications as the complete roll out of the AES will take some years to materialize. To date, the only practical attack on the DES is the exhaustive key search. In this paper, we exploit a recently presented sliding property of the DES key schedule to show that the exhaustive key search of the DES can be further reduced from previous known results.