A cryptanalysis procedure of the data encryption standard

In this paper an attack strategy on the Data Encryption Standard (DES) that is different from the existing ones is developed. The attack strategy is based on a theorem proved by the author, called LR theorem. The attack can be done by means of a personal computer, i.e. a Pentium IV based machine. Obviously, more information than a sample of plaintext and ciphertext is required. However, this additional requirement is reduced to a minimum of just 24 bits. The LR theorem uncovers 16 trapdoors of which 2 are of importance. With this knowledge, an attack on Triple-DES can be performed using the aforementioned personal computer. A simple solution to this kind of attack is proposed, preserving the complexity of the Triple-DBS, 2¹¹².