boltlabs-inc / tss-ecdsa

An implementation of a threshold ECDSA signature scheme
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Add size verification for Paillier public keys #466

Closed marsella closed 11 months ago

marsella commented 1 year ago

The recent GG18/20 vulnerability hinges on signer's Paillier public keys having no small factors.

CGGMP avoids most of this by including ZK proofs that validate that the public keys are the product of two primes and that neither factor is "too big" (which would force the other factor to be too small if the overall modulus is large). However, I think we don't check the size of public Paillier moduli we receive from other parties, so small moduli might have small factors.