In this paper, a hash function with lower rate but higher efficiency is proposed and it can be built on insecure compression functions. The security of this scheme is proved under black-box model and some compression function based on block ciphers are given to build this scheme. It is also shown that key schedule is a more important factor affecting the efficiency of a block-cipher-based hash function than rate. The new scheme only needs 2 keys and the key schedule of it can be pre-computed. It means the new scheme need not re-schedule the keys at every step during the iterations and its efficiency is improved.%提出了一个基于分组密码的hash函数体制,它的rate小于1但却具有更高的效率,同时,这个hash函数可以使用不安全的压缩函数进行构造,降低了对压缩函数安全性的要求.首先,在黑盒子模型下对这个新的体制的安全性进行了证明,然后给出了能够用于构造该体制的使用分组密码构造的压缩函数,最后通过实验对比发现,新hash函数的速度比rate为1的hash函数快得多.实验结果表明,除了rate以外,密钥编排也是影响基于分组密码hash函数效率的重要因素,甚至比rate影响更大.该体制只有两个密钥,不需要进行大量的密钥扩展运算,大大提高了基于分组密码hash函数的效率,而且该体制可以使用现有的分组密码来构造.
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