cpp-lwevss

C++ implementation of VSS using LWE encryption and proofs, as described in the article:

Practical Non-interactive Publicly Verifiable Secret Sharing with Thousands of Parties, by Craig Gentry and Shai Halevi and Vadim Lyubashevsky, Cryptology ePrint Archive: Report 2021/1397.

This implementation was written mostly by Shai Halevi. It is a proof-of-concept and is not suitable for use in production. The code is documented internally, and we made some effort to separate out performance-sensitive parts so they can be optimized on their own.

Structure

This is a cmake project, but the directory structure tries to mimic Go conventions to some extent. Different subdirectories of src correspond roughly to what the Go packages would be. Current subdirectories are:

• 25519 - wrapper around libsodium, namespace CRV25519. Provide classes Point and Scalar. See point25519.hpp, scalar25519.hpp in the include directory.

• algebra - wrapper around NTL, namespace ALGEBRA. Should make using packages other than NTL in the future a little easier. See algebra.hpp in the include directory.

• dlproofs - implementation of Bulletproofs-like proofs, namespace DLPROOFS. Provides proofs for linear and quadratic constraints, as well as proving the norm-squared (mod P) of a vector. See constraints.hpp pedersen.hpp bulletproof.hpp in the includes directory.

• tools - currently contains only tools related to Shamir secret sharing, namespace TOOLS. See shamir.hpp in the includes directory.

• regev - implementation of Regev encryption and proofs related to it, namespace REGEVENC. See regevEnc.hpp and regevProofs.hpp in the includes directory.

• libmerlin - Henry de Valence's one-file "C" implementation of Merlin transcripts. Taken (with minor fixes) from https://github.com/hdevalence/libmerlin (commit 4bf6228), but separated the "c" and "h" files to different directories. A C++ wrapper found in merlin.hpp in the include directory.

Dependencies

• libsodium for implementation of arithmetic over Curve25519

• NTL and GMP underlying operations for Regev encryption

License

This implementation is provided under the MIT license