Improving Linear Key Recovery Attacks using Walsh Spectrum Puncturing

ePrint Report: Improving Linear Key Recovery Attacks using Walsh Spectrum Puncturing

Antonio Flórez-Gutiérrez, Yosuke Todo

In some linear key recovery attacks, the function which determines the value of the linear approximation from the plaintext, ciphertext and key is replaced by a similar map in order to improve the time or memory complexity at the cost of a data complexity increase. We propose a general framework for key recovery map substitution, and introduce Walsh spectrum puncturing, which consists of removing carefully-chosen …

attacks ciphertext eprint report function key linear map memory order plaintext recovery report spectrum todo value