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taurushq-io / multi-party-sig

Implementation of protocols for threshold signatures
Apache License 2.0
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fix issues of unsuccessful proveNth verification in presign #78

Closed zzyalbert closed 1 year ago

zzyalbert commented 2 years ago

I think the verification of proveNth is wrong in presign.

The msg.Nonce is the encryption of Paillier, so it should be in range of mod N^2 instead of mod N.

Also the deltaProof dosen't match DeltaCiphertext in verification and that issue exists in chiProof/ChiCiphertext as well.

adr1anh commented 2 years ago

Good catch for the [from][id] -> [id][from], the verification would have failed. I'm not sure about the nonce being in $\mathbb{Z}{N^2}^\star$ though, since Paillier nonces are defined as elements in $\mathbb{Z}{N}^\star$ (see Def 2.2 of the paper).