rkvc

rkvc is a library for building anonymous credentials from algebraic MACs, based on the techniques described in Revisiting Keyed-Verification Anonymous Credentials, and in prior works¹.

Project Structure

The project consists of several components:

• src/: Core library implementation

  • attributes.rs: Attributes system for credential data
  • cmz.rs: CMZ credential scheme implementation
  • hash.rs: Cryptographic hashing utilities
  • pederson.rs: Pedersen commitment scheme
  • range.rs: Range proofs with Bulletproofs
  • zkp.rs: Zero-knowledge proof primitives

• derive/: Procedural macros for attribute definitions

• examples/: Sample implementations demonstrating library usage

Getting Started

Prerequisites

• Rust 1.85 or later
• cargo expand is required for macro tests
  • cargo install --locked cargo-expand

Building

cargo build

Running Tests

cargo test --workspace

Updating macro tests

When developing the macro implementation, test vectors can be updated with the following command.

TRYBUILD=overwrite MACROTEST=overwrite cargo test -p rkvc-derive

Examine the changes and check commit them with git if they are as expected.

Development Commands

# Code linting
cargo clippy

# Code formatting
cargo fmt

Features

• default: Includes derive feature
• derive: Enables derive macros for attributes
• std: Standard library support (disabled by default for no_std compatibility)

Examples

Several examples are provided to demonstrate library usage:

• expiration.rs: A simple credential with an ID and expiration time.
• lox.rs: Example implementation of Lox.
• ooni.rs: Example implementation targeting the use case of OONI.

Run examples with:

cargo run --manifest-path examples/Cargo.toml --bin ${EXAMPLE:?}

Footnotes

1. TODO: List prior works e.g. CMZ'14 and BBDT'16 ↩