The Data Encryption Standard (DES) and its strength against attacks

The Data Encryption Standard (DES) was developed by an IBM team around 1974 and adopted as a national standard in 1977. Since that time, many cryptanalysts have attempted to find shortcuts for breaking the system. In this paper, we examine one such attempt, the method of differential cryptanalysis, published by Biham and Shamir. We show some of the safeguards against differential cryptanalysis that were built into the system from the beginning, with the result that more than 10
¹⁵
bytes of chosen plaintext are required for this attack to succeed.