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Wang's (et al) differential attack works on MD5, MD4, RIPEMD and HAVAL.

Why doesn't it work on SHA-1?

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  • $\begingroup$ The website sites.google.com/site/itstheshappening has the details of another attack on SHA-1 from Marc Stevens (CWI, the Netherlands), Pierre Karpman (Inria, France and NTU Singapore) and Thomas Peyrin (NTU Singapore). $\endgroup$ – kodlu Dec 23 '16 at 3:12
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The message expansion step in SHA-1. The compression functions for MD4,MD5, RIPEMD and I think HAVAL only re-arrange and re-use words in the message block.

SHA-1 will expand the message from 16 words to 80 words using a rotation and XOR operation. The additional 64 words are a function of every word of the message block.

Because of this additional dependence on previous words in the block, Wang's attack will not work.

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