Linear Cryptanalysis

Linear cryptanalysis is a known-plaintext attack that exploits linear approximations of a cipher's non-linear transformations to recover secret key bits. Introduced by Mitsuru Matsui in 1993, linear cryptanalysis provides practical attacks on ciphers like DES with computational complexity less than brute force. The technique analyzes statistical biases in how linear combinations of plaintext and ciphertext bits relate to key bits, enabling key recovery with reduced data requirements.