Security Increasing of Hash Functions in Information Systems on the Basis of Multi-Iterative Hashing Algorithm with Several Modifiers

In this paper influence of multi-iterative hashing with several modifiers algorithm's parameters on its cryptographic persistence is considered. Relevance of multi-iterative hashing with several modifiers algorithm's application and need of research of its parameters are justified, the description of algorithm is provided. Cryptographic persistence of hash function to attacks which are not depends on algorithm is caused by its bitness, i.e. actually on the amount of unique hash values that hash function is able to generate. For an estimation of algorithm's persistence to dictionary attacks and attacks by methods of "brute force" and "birthdays" the algorithm of multi-iterative hashing with several modifiers is considered as independent hash function. Estimation of the algorithm's persistence for a given number of iterations is offered to produce by calculating the average bitness of equivalently persistent hash function for the algorithm. The description of estimation method of algorithm's persistence is provided. The experiments are performed using a truncated cryptographically persistent hash function. The results of experiments allow to compare the algorithm's persistence metrics of under different values of its parameters. Besides, the results of the experiments allow to understand how the values of certain parameters, and combinations of values for these parameters affect for the algorithm's cryptographic persistence to dictionary attacks and attacks by methods of "brute force'' and "birthdays''. On the basis of the received results it is possible to draw conclusions about the values of the parameters recommended for practical application of this algorithm. In conclusion, the paper presents the main results of the work. Authors of the article believe that the algorithm can find application in authentication subsystems of information systems, and also in systems where the most important requirement is persistence for a long time.