Design And Application Of The Single-Block Hash Function

Due to the rapid development of Internet technology, interactive mode including the electronic commerce and network conversations have become essential ways of daily communication in people’s life. To guarantee the security of these communications, hash functions are widely adopted in c necking the integrity of the data that transferred through the internet. A plenty of researchers proposed that the increase in both the length of the hash blocks and the output could lead to enhanced security of the hash function. However, the problem of studying and designing hash functions that work for short message remain to be solved.In this dissertation, we aimed to design the Single-Block hash function for the short message (SBH). Firstly, we focus on two sizes of the input bits:SBH-128is the hash function for the messages that are short than128bits; SBH-256works for the messages that are between128bits and256bits. The new functions are created in accordance with the standards of designing hash functions, including the initialization process for input messages, block structuralization such as the block size, definition of four nonlinear functions and related parameters in each round, etc.The second part involves the program implementation of the new hash function according to its design and the algorithmic logic. Furthermore, several comparative experiments were conducted between the new hash and two traditional hash functions, MD5and SHA-1, in terms of processing time. The efficiency of new hash was analyzed on the basis of the experimental data.Lastly, results of experiments indicated that, compared with traditional hash functions, new hash has better performance in respect of the processing time. Results showed that the average efficiency of SBH-128is7.4%higher than MD5,25.4%higher than SHA-1; SBH-256is5.2%higher than MD5, while22.9%higher than SHA-1. Besides, the same with MD5, the output of SBH is128bits, which indicates a same level of security with MD5. Therefore, new function not only ensured the security property but also covered the shortages of traditional ones while dealing with short messages. In addition, we applied SBH-128to an identify authentication system frame so as to m ake the system achieve the integrity checking by itself. Also, we applied hash algorithm in digital certificate based on SBH-256.