Questions tagged [gimli]

Question related to Gimli : usage, security, cryptanalysis.

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Provably secure way of expanding permutations

Gimli is a 384-bit permutation that makes use of an internal 96-bit permutation which works on columns. Every 4 rounds starting from the 1st a "small swap" is performed and every 4 rounds ...
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How to fix the issue with Gimli full permutation distinguisher?

A new paper "New results on Gimli: full-permutation distinguishers and improved collisions" has been published stating a full 24-round permutation distinguisher with a cost of $2^{64}$ and ...
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CSPRNG for Contract Bridge (RAND_MAX = 0xAD55E315634DDA658BF49200)

Some background information: In contract bridge, there are 0xAD55E315634DDA658BF49200 (just under 2^96) possible bridge deals. Since the 1990s, bridge deals for major tournaments were generated on ...
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The Gimli non-linear operator

NORX replaces all the additions of the Chacha20 quarter-round function with the non-linear $x \oplus y \oplus ((x \land y) \ll 1)$ operation. Gimli supposedly improves on it with $x \oplus y \oplus ((...
4
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1answer
665 views

How to build disk encryption system using forward permutations like Gimli?

First of all, this is purely a thought experiment. The width of Gimli isn't even a power of two (384 bits), and secondary storage bus speeds aren't even worth using a high performance permutation like ...
4
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1answer
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How to construct a “toy” version of Gimli permutation for three (instead of twelve) 32-bit words?

I am interested to see a "toy" version of the Gimli permutation for three (instead of twelve) 32-bit words. I see that the "core" sub-permutation of Gimli operates on three 32-bit words, but I don't ...
4
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1answer
447 views

Can ChaCha20 be repurposed as a general purpose permutation function like Gimli?

I like the idea behind Gimli and libhydrogen but in my benchmarks Gimli permutation function is considerably slower than ChaCha20 one. By considerably I mean four times slower using SIMD builtins. ...
13
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Doubt about published test vectors for gimli hash

In https://eprint.iacr.org/2017/630.pdf and https://gimli.cr.yp.to/gimli-20170627.pdf there are test vectors for the gimli hash function. I have compile the reference C code test_hash.c from https://...