S1 = single source, version 1: verifying membership in a single Data Group
Currently, the proving scheme is utilized by the ZK Badge protocol, which is no longer maintained. It allows users to verify membership in a Data Group from a single Data Source and mint a ZK Badge on an unlinked Ethereum address.
Sismo’s ZK Badge protocol uses Hydra S1 proving schemes to issue ZK Badges. You can see them here. While the contracts are still deployed, Sismo no longer maintains the ZK Badge protocol. Read more in this blog post.
Hydra Proof of Ownership
The Hydra-S1 proving scheme allows participants to establish, in one ZK proof, that for a given Proof Identifier: