Define Differential Cryptanalysis

Question

Give a brief explanation of the term Differential Cryptanalysis.

Answer 1

Differential cryptanalysis is a sort of attack which can be mounted on iterative block ciphers. Such methods were first introduced through Murphy [Mur90] in an attack on the FEAL-4, however they were later enhanced and perfected by Biham and Shamir who employed them to attack DES. Differential cryptanalysis is essentially a selected plaintext attack and relies on the analysis of evolution of differences between two connected plaintexts as they are encrypted under same key. By careful analysis of the accessible data, probabilities can be allocated to each of the possible keys as well as eventually the most probable key is identified as correct one.