Ciphers Question:

Linear cryptanalysis was first devised by Matsui and Yamagishi in an attack on FEAL. It was extended by Matsui to attack DES. Linear cryptanalysis is a known plaintext attack and uses a linear approximation to describe the behavior of the block cipher. Given sufficient pairs of plaintext and corresponding ciphertext, bits of information about the key can be obtained and increased amounts of data will usually give a higher probability of success.