Differential Analysis Of Lightweight Block Cipher GIFT

With the development of information technology,people have higher demand for information security.People are always facing the challenge of information security in this digital and intelligent era.Cryptography plays an important role in information security protection.Block cipher,as an important branch of cryptography,plays an irreplaceable role in the field of information security.In some environments with limited computing resources,lightweight block cipher algorithm is the only choice to protect information security,so the research on lightweight block cipher algorithm has very important practical significance.GIFT is a lightweight block cipher designed by Banik et al.at the 10th anniversary of the launch of PRESENT.GIFT adopts SPN structure,which is very similar to PRESENT.GIFT has a simpler structure and higher efficiency compared with PRESENT.It has two versions of 64-bit and 128-bit,namely GIFT-64 and GIFT-128.Both versions have a key length of 128 bits.The number of iteration rounds are 28 and 40,respectively.In this paper,we improve a two-step algorithm to search for differential characteris-tics.This two-step algorithm is based on Mixed-Integer Linear Programming?MILP?.For GIFT-128,due to its large number of rounds and large state space,the two-step algorithm is improved in the search process.In this paper,a programming solver,Gurobi is used to solve these problems and the following results are obtained:·For GIFT-64,we find a 12-round differential trail with probability 2^-59and eight 4-round iterative differential trails.We launch a key recovery attack on 19-round GIFT-64 by using a 12-round differential trail with probability 2^-60.·For GIFT-128,we find a 18-round differential trail with probability 2^-109and we give a key recovery attack on 22-round GIFT-128.