Multi-Property-Preserving Hash Domain Extension and the EMD Transform
Multi-Property-Preserving Hash Domain Extension and the EMD Transform
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DOI：
10.1007/11935230_20
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发表时间：
2006-12
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影响因子：
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通讯作者：
M. Bellare;Thomas Ristenpart
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文献类型：
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作者：
M. Bellare;Thomas Ristenpart
我们指出了Coron等人定义和实现的Hash函数域扩张变换的看似强伪随机预言保性(PRO-PR)性质。[1]实际上会削弱我们对散列函数的保证，特别是产生即使应用变换的压缩函数是CR也不能抗偶碰撞(CR)的散列函数。这不仅在一般情况下是正确的，而且我们证明了文献[1]中提出的所有变换都有这个弱点。我们建议，下一代哈希函数的域扩展变换的适当目标是保持多属性，即至少同时具有抗碰撞、保伪随机函数和保伪随机函数的变换。我们提出了一种有效的新变换，证明了它在这个意义上是多属性保持的。
We point out that the seemingly strongpseudorandom oracle preserving(PRO-Pr) property of hash function domain-extension transforms defined and implemented by Coron et. al. [1] can actuallyweakenour guarantees on the hash function, in particular producing a hash function that fails to be even collision-resistant (CR) even though the compression function to which the transform is applied is CR. Not only is this true in general, but we show thatallthe transforms presented in [1] have this weakness. We suggest that the appropriate goal of a domain extension transform for the next generation of hash functions is to be multi-property preserving, namely that one should have asingletransform that is simultaneously at least collision-resistance preserving, pseudorandom function preserving and PRO-Pr. We present an efficient new transform that is proven to be multi-property preserving in this sense.