New answers tagged 2nd-preimage-resistance
Can we exhibit collisions, or second-preimages (with implies the former), for the ChaCha core? No, likely not. The Salsa20 and ChaCha cores both consist of a large number of "quarter-rounds" each of which is invertible and bijective. The only reason neither core is a bijection (and thus can have collisions) is the final addition of the input elements ...
The easiest, zero thought, way to get an answer to this question is to ask the computer. Using Dylan's cryptol implementation it is straight-forward to ask a question: m1 != m2 ==> ChaChaCore m1 != ChaChaCore m2 That is, if inputs m1 and m2 are not equal then the ChaCha core function will not be equal either. Cryptol doesn't (well, didn't) have an ...
Yes. I believe this is the standard conversion. (That link is to the paper "Universal One-Way Hash Functions via Inaccessible Entropy".)
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