equality_across_groups

Protocols for proving equality of committed values across groups.

• Implements the sigma protocol for proving that two values committed in different groups are equal. As described in Figure 1 and its extension in section 5 of the paper Proofs of discrete logarithm equality across groups. Check the module for more docs
• Implements the protocol to prove short Weierstrass elliptic curve point addition and scalar multiplication from the paper CDLS: Proving Knowledge of Committed Discrete Logarithms with Soundness. Check the point addition module and scalar multiplication module for more docs
• Use the above protocols to prove knowledge of a committed ECDSA public key on Tom-256 curve as described in the paper ZKAttest Ring and Group Signatures for Existing ECDSA Keys. Check the module for more docs
• Use the above protocols to prove knowledge of a committed ECDSA public key on BLS12-381 curve. Check the test pok_ecdsa_pubkey_committed_in_bls12_381_commitment in module.

CREDIT

This idea of using these 2 protocols to prove knowledge of ECDSA public key committed on the BLS12-381 curve came from Patrick Amrein from Ubique and their work here is prior art.