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After tinkering with cryptographic hash functions, I started wondering if they do have counterpart functions that would imitate their cryptographic properties but with a lower level of strength in terms of their time/space complexity.

For instance, if I were to test certain collision algorithms in a simplified version of SHA1, which let's call SHA1-light, and it took X minutes to generate a collision, then I could estimate that it would take Y minutes in the standard SHA-1.

My interest lies in reproducing some of the well-known attacks, such as the Shambles attack on SHA-1, without necessarily having to spend $10k to verify if I have implemented the algorithm correctly.

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    $\begingroup$ Just a thought, but I guess for these kind of things the reduced rounds versions of any hash would be interesting to attack. I'm not entirely sure if it is any help w.r.t. the Shambles / chosen prefix attack though. $\endgroup$
    – Maarten Bodewes
    Commented Apr 9, 2023 at 23:12
  • $\begingroup$ @MaartenBodewes How to be entirely sure then, any hint or pointer I can follow? $\endgroup$
    – Ryan B.
    Commented Apr 10, 2023 at 13:17
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    $\begingroup$ My gut feeling: those attacks depend on hash function design structure and simple cutting down of bitwidth or reducing rounds is not likely to be easily tractable in terms of giving you some ratio in terms of collision (or other) attack time conversion $\endgroup$
    – kodlu
    Commented Apr 10, 2023 at 18:11

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