# proof_system
The goal of this crate is to allow creating and combining zero knowledge proofs by executing several
protocols as sub-protocols.
The idea is to represent each relation to be proved as a [`Statement`], and any relations between
[`Statement`]s as a [`MetaStatement`]. Both of these types contain public (known to both prover
and verifier) information and are contained in a [`ProofSpec`] whose goal is to unambiguously
define what needs to be proven. The prover then uses a [`Witness`] per [`Statement`] and creates a
[`StatementProof`] per [`Statement`]. All [`StatementProof`]s are grouped together in a [`Proof`]
and the verifier then uses the [`ProofSpec`] and [`Proof`] to verify the proof. Currently it is
assumed that there is one [`StatementProof`] per [`Statement`] and one [`Witness`] per [`Statement`]
and [`StatementProof`]s appear in the same order in [`Proof`] as [`Statement`]s do in [`ProofSpec`].
[`Statement`], [`Witness`] and [`StatementProof`] are enums whose variants will be entities from different
protocols. Each of these protocols are variants of the enum [`SubProtocol`].
Currently supports proof of knowledge of BBS+ signature, accumulator membership, accumulator
non-membership, and Pedersen commitment pre-image. The tests show how to create a proof that combines
several proofs of knowledge.
BBS+ signature and prove equality between the messages and also proof that combines proof of knowledge of
BBS+ signature, accumulator membership,accumulator non-membership, and Pedersend commitment pre-image.
See tests for examples.
*Note*: This design is largely inspired from my work at Hyperledger Ursa.
*Note*: The design is tentative and will likely change as more protocols are integrated.
[`Statement`]: crate::statement::Statement
[`MetaStatement`]: crate::statement::MetaStatement
[`ProofSpec`]: crate::proof::ProofSpec
[`Witness`]: crate::witness::Witness
[`StatementProof`]: crate::proof::StatementProof
[`Proof`]: crate::proof::Proof
[`SubProtocol`]: crate::sub_protocols::SubProtocol
License: Apache-2.0