Interface EthereumGroupPCDProof

A hex string of the NIZK proof format defined in https://github.com/personaelabs/spartan-ecdsa

In the group membership proof, the semaphore identity is used as the message to sign.

https://github.com/personaelabs/spartan-ecdsa/blob/5dae5e1aa4eda726ddffc08eaec0144d003a98a0/packages/Spartan-secq/src/lib.rs#L491

https://github.com/personaelabs/spartan-ecdsa/blob/5dae5e1aa4eda726ddffc08eaec0144d003a98a0/packages/Spartan-secq/src/r1csproof.rs#L23

A signature of the serialized spartan-ecdsa group membership proof, using a semaphore identity.