可用于哈希函数的安全迭代结构

Iterative Structure for Hash Function

Merkle-Damgard(MD)迭代结构存在着不能保持压缩函数的第2原像稳固性、伪随机函数性等不安全性问题.为增强迭代哈希函数的安全性,从抵抗现有攻击的角度提出1个强化MD迭代结构,称为CMD结构.经证明,该结构可以保持压缩函数的抗碰撞性,能抵抗现有的对MD迭代结构的攻击,包括第2原像攻击和任意选定前缀的原像攻击.利用这些攻击方法对enveloped Merkle-Damgard结构进行了分析,并指出该结构不能提供比MD结构更高的安全性.

Merkle-Damgard construction had been found that it could not preserve all of the properties of the compression function, such as the second preimage resistance property, pseudo random property etc. To improve the security of the iterative Hash function, an enhanced iterative construction, called CMD construction was proposed. This construction can maintain the collision resistance of the compression function. The analysis results show that it can resist the attacks on the Merkle-Damgard construction, including the second preimage attack and the herding attack. In addition, using these known attack methods, the security of the enveloped Merkle-Damgard construction is showed to be the same as that of the Merkle-Damgard construction.