Security Evaluation of Light-weight Block Ciphers by Gpgpu

Nowadays, general purpose graphical processing unit (GPGPU) has been used in many ares. We use it for security evaluation of light-weight block ciphers. Light-weight block cipher is one of key technologies for small communication devices such as sensor network. To design a light-weight block cipher whose fastness and security are balanced, so that, its security margin should be evaluated exactly. One of security evaluation method, we focus on integral attack which exploits integral distinguisher to recover some round keys. Integral distinguisher is the main factor of integral attack, and it can be obtained by computer experiment. We use GPGPU to accelerate computer experiment. We propose an algorithm to search for upper bound of integral distinguisher by GPGPU. There are theoretical and experimental steps. We specify lower order integral distinguisher from upper bound one in the theoretical step. Such integral distinguisher is tested by computer experiment in the experimental step. By applying the proposal algorithm to HIGHT, TWINE, LBlock, PRESENT and RECTANGLE, we obtain more advantageous results.