Haval And Some Of The New Hash Function Analysis

With the wide application and indepth development of computer networks, information security has been valued by the community and have became an important factor in affecting national security, economic development and social stability. As the core of information security technology from morden cryptography, making of morden cryptography technology into the field of information science research foucs. Hash function is an important branch of cryptography. It is a non-reversible and one-way cryptosystem which transforms the input of arbitrary length into fixed-length output. Hash function has a wide range of applications in the digital signature and message integrity detection.Haval was presented by Yuliang Zheng et al. at Auscrypto'92. It can be processed in 3, 4 or 5 passes, and produces 128, 160, 192, or 224-bit fingerprint. Finding hash collisions achieved much attention since Professor Xiaoyun Wang publicize their work in Crypto' 2004. Rumba20 algorithm is a compression function which is based on stream cipher Salsa20. Its input is 1536 bits and output is 512 bits. Rumba20 is designed to provide collision resistance at high speed. Therefore, executing safety analysis of Haval-128 algorithm and the algorithm of Rumba20 has a certain cryptographic significance. Some achievements have been obtained in this paper:1. We propose a new one bit difference collision attack of hash function Haval-128, our attack crown all present methods on constructing hash collisions. We give all the differential characteristics and a set of suffcient conditions that guarantee all the differential characteristics to occur in the collision. The attack's running time is less than 226 2-pass Haval computations.2. We deduce the conditions which can decrease the computational complexity by three message modification methods and give the algorithm of our attack.3. This paper describers the differential analysis in Rumba algorithms application, and gives the way to choose the messages difference, the method of determining the path difference, the method of deriving the sufficient conditions which ensure the establishment of differential path and we introduced a method of neutral bits in the analysis of the Rumba algorithm. Based on these, we have summarized the general steps of using the differential analysis to attack Hash functions.