Research Of Cache Attack On DES

Information security is not only concerned by the governments and the military sectors, but also by the Enterprises .So United States National Bureau of Standards (NIST) published an algorithm developed by IBM, and ratify it as the Data Encryption Standard for the non-confidential departments in 1977, DES is the acronym. Since its publication, it has become the major encryption algorithms for confidential communications of international commerce and computer. DES has become a well known and widely used cryptosystem for many years.However, DES has major weakness because of the only 56-bit-long key size and the 64-bit-long block size. When it came to 1990s, Eli Biham and Adi Shamir proposed differential cryptanalysis, and Mitsuru Matsui proposed the linear cryptanalysis. But both the methods need huge number of plaintexts to decrypt the key.Side-channel attack is a new method to analysis cryptography. It makes use of the environment information which is generated in encryption to decrypt the cryptography. It has been an effective method. Cache attack is one kind of side-channel attack that based on cache. It makes use of the cache feature to gain some information of the key. It can be used for all DES algorithm that implemented with table-lookup and run under the machine with cache, so it can harm many computer system, such as server, desktop and embedded system.At present, there have been some papers about how to use cache to attack DES encryption. In 1996 Paul Kocher first proposed the side channel attacks and did some research on the power analysis attack. J. Kelsey, B. Schneier, D. Wagner, and C. Hall put forward cache analysis attacks while the domestic related research just made the first step. So this paper intends to make use of the cache attack to DES to explore the cache analysis method and put forward defensive measures. According to the characteristic of hitting or missing showed by the visiting arrays cache operation in the DES encryption progress, this paper proposes a analysis technique of cache attack to DES. On the basis of the DES algorithm and Cache structure, we introduce the principle of DES, and analysis two attacking models and implemented it.