All the implementations in this repository constitute a first step towards providing "low-end" devices with post-quantum security.
In this repository, one can find implementations of PICNIC and SPHINCS+ using the lightweight ciphers ASCON and SKINNY.
Additionally, I implemented a successful attack against the SPHINCS+ scheme with a hypertree of size 28. Furthermore, in this attack, the higher the hypertree, the smaller the time difference between forging one or hundreds of signatures (maybe thousands :) ).
Results:
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PICNIC: Applying either ASCON or SKINNY results in faster signatures than the original cipher but double the signature size.
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SPHNICS+: ASCON provides faster signing speeds.
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SPHINCS+ Attack: The time it takes to forge one signature for a hypertree of size 28 is five days.