MPC-Ristretto

This library provides an abstraction over the curve25519-dalek arithmetic implementations (repo) that allows for secret-sharing based MPC computations over the algebra. As well, this library includes SPDZ style share authentication for maliciously secure computation.

Organization

The core of the library lives in src/, and the integration tests live in integration/. The source folder is organized as follows:

• network.rs and network/ define a P2P transport on top of QUIC (using quinn) in which two peers open up a bi-directional stream to communicate about Scalar and RistrettoPoint types.
• mpc_scalar.rs and mpc_ristretto.rs define an unauthenticated (semi-honest secure) wrapper around the Dalek Scalar and RistrettoPoint respectively. These implementations override arithmetic operations such that the result of these operations is a valid secret sharing of the underlying result. This includes use of the Beaver Trick for multiplication.
• authenticated_scalar.rs and authenticated_ristretto.rs define authentication wrappers around MpcScalar and MpcRistrettoPoint that maintain SPDZ style MACs throughout the computation. These wrappers can be opened in an authenticated commit/reveal interaction that ensures their results have not been tampered with.
• commitment.rs defines commitment implementations for both Scalar values (Pedersen) and RistrettoPoint values (SHA3_512 hash commitment).
• macros.rs defines a series of macros used to aid in arithmetic implementation for borrowed values, wrapped values, etc.
• beaver.rs defines an interface the library expects to receive Beaver triplets through. Because the preprocessing functionality is largely an infrastructural burden, only dummy implementations are given. The consumer of this library should implement an appropriate pre-processing functionality.
• fabric.rs defines an "MPC Fabric" that effectively acts as a dependency injection layer on top of the network. That is, the MpcFabric holds network references, beaver source implementations, and MAC keys; allowing the consumer of the library to allocate secret shared values without passing around these dependencies.

Tests

Unit tests for isolated parts of the library are available via bash cargo test --lib

The bulk of this library's testing is best done with real communication; and so most of the tests are integration tests. The integration tests can be run as bash ./run_integration.zsh or more directly as bash docker compose up