Method for structuring one-way Hash function based on random function

Abstract

The invention belongs to the field of information security, in particular to the field of cryptology. The invention relates to a method for structuring a one-way Hash function based on a random function. The method uses a random function as a Hash function, or rather, the method uses the random function as a compression function, namely the compression function is indeterminate and has various possible concrete function forms, and the concrete form of the function is determined through clear text messages during calculation. The Hash function structured by the method brings various obstacles for decoding, a forged clear text needs to conform to the requirements of the traditional deterministic Hash function, and the definite code of the concrete function form of the deterministic random Hash function corresponding to the clear text must be consistent. The current cryptanalysis generally aims at the deterministic Hash function. When a cryptanalyst only knows a Hash value, decoding is even more difficult. As the concrete function form of the random function is not known, the cryptanalyst is unable to start by adopting a general decoding method.

Description

technical field [0001] The invention belongs to the field of information security and relates to a method for constructing a one-way hash function based on a random function. Background technique [0002] The existing hash (also translated as hash, hash, hash) function has a fixed structure and function, which provides convenience for cryptanalysis. For the hash function H=Hash(M), it is generally easy to calculate H through M, but it is very difficult to find one or more corresponding M through H, and it often takes a long time under limited computing power. However, in recent years, Wang Xiaoyun has cracked a series of hash functions. In 2004 and 2005, the research team led by Wang Xiaoyun successively deciphered two major cryptographic algorithms, MD5 and SHA-1, which are widely used in computer security systems all over the world, which aroused great concern and high praise from the international cryptography community. For a fixed function, it is more difficult to ens...

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Problems solved by technology

In 2004 and 2005, the research team led by Wang Xiaoyun successively deciphered two major cryptographic algorithms, MD5 and SHA-1, which are widely used in computer security systems all over the world, which aroused great concern and high praise from the international cryptography community. For a fixed function, it is more difficult to ensure this one-way, because in principle, it can be reversed according to the structure of the hash function (although it is one-way, the original text and the hash value are a many-to-one mapping relationship , but with the help of some mathematical methods and calculation tools, it is possible to carry out successful reverse deduction, which provides an entry point for cracking), it is necessary to design the algorithm very complicated

If the algorithm of a hash function is random and uncertain, it is difficult for cryptanalysts to start

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