Curv

Curv contains an extremly simple interface to onboard new elliptic curves. Use this library for general purpose elliptic curve cryptography.

The library has a built in support for some useful operations/primitives such as verifiable secret sharing, commitment schemes, zero knowledge proofs, and simple two party protocols such as ECDH and coin flip. The library comes with serialize/deserialize support to be used in higher level code to implement networking.

Currently Supported Elliptic Curves

Curve	low level library	curve description	blockchain usage examples
Secp256k1	rust-secp256k1	bitcoin wiki	Bitcoin, Ethereum
Ed25519	cryptoxide	BDLSY11	Ripple, Tezos, Cardano
Jubjub	librustzcash	what is jubjub	Zcash
Ristretto	curve25519-dalek	ristretto group	not yet ;)

Security

The library was audited by Kudelski security on Feb19. The report can be found here. No critical issue were found and all issues found were fixed.

The code was reviewed independently by few other cryptographers. Special thanks goes to Claudio Orlandi from Aarhus University.

In general security of the library is strongly dependent on the security of the low level libraries used. We chose only libraries that are used as part of other big projects and went through heavy audit/review.

The library is not immune to side channel attacks but considerable effort was given to try and catch as many such attacks as possible (see audit report).

Build

By default cargo build will build the library only for BigInt (used for example in rust-paillier). To add opertions for one of the elliptic curves a feature must be specified:

• cargo build --features=ec_secp256k1 for secp256k1
• cargo build --features=ec_ed25519 for ed25519
• cargo build --features=ec_jubjub for jubjub
• cargo build --features=ec_ristretto for ristretto

Examples

The library includes some basic examples to get you going. To run them: cargo run --example EXAMPLE_NAME --features CURVE_NAME for example: cargo run --example proof_of_knowledge_of_dlog --features ec_jubjub

Docs

Docs are built per elliptic curve, use cargo doc --no-deps --features CURVE_NAME. for example: cargo doc --no-deps --features ec_ed25519

Adding New Elliptic Curve

To add support for new elliptic curve simply fill in the ECScalar and ECPoint traits.

License

Curv is released under the terms of the MIT license. See LICENSE for more information.

Development Process

We use several methods to communicate: You can open an issue, reach out by mail or join the KZen Research Telegram for discussions on code and research. Changes are to be submitted as pull requests.

Contact

For any questions, feel free to email us.