diff --git a/Cargo.lock b/Cargo.lock index 33d30686..9187f0c8 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -663,6 +663,13 @@ dependencies = [ "subtle", ] +[[package]] +name = "vrf" +version = "0.1.0" +dependencies = [ + "digest 0.11.0-pre.10 (registry+https://github.com/rust-lang/crates.io-index)", +] + [[package]] name = "wasi" version = "0.13.3+wasi-0.2.2" diff --git a/Cargo.toml b/Cargo.toml index 21a73466..afcd225a 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -13,6 +13,7 @@ members = [ "signature_derive", "universal-hash", "signature", + "vrf", ] [patch.crates-io] diff --git a/vrf/CHANGELOG.md b/vrf/CHANGELOG.md new file mode 100644 index 00000000..15a61afa --- /dev/null +++ b/vrf/CHANGELOG.md @@ -0,0 +1,8 @@ +# Changelog + +All notable changes to this project will be documented in this file. + +The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), +and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). + +## [Unreleased] diff --git a/vrf/Cargo.toml b/vrf/Cargo.toml new file mode 100644 index 00000000..c8f78ce9 --- /dev/null +++ b/vrf/Cargo.toml @@ -0,0 +1,11 @@ +[package] +name = "vrf" +description = "Traits for verifiable random functions (VRFs)" +version = "0.1.0" +authors = ["RustCrypto Developers"] +license = "Apache-2.0 OR MIT" +edition = "2024" +keywords = ["crypto", "ecvrf", "vrf"] + +[dependencies] +digest = { version = "=0.11.0-pre.10", default-features = false } diff --git a/vrf/LICENSE-APACHE b/vrf/LICENSE-APACHE new file mode 100644 index 00000000..78173fa2 --- /dev/null +++ b/vrf/LICENSE-APACHE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + +TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + +1. 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IN NO EVENT +SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR +IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +DEALINGS IN THE SOFTWARE. diff --git a/vrf/README.md b/vrf/README.md new file mode 100644 index 00000000..c33f37b1 --- /dev/null +++ b/vrf/README.md @@ -0,0 +1,22 @@ +# [RustCrypto]: Verifiable Random Functions + +## SemVer Policy + +- All on-by-default features of this library are covered by SemVer +- MSRV is considered exempt from SemVer as noted above + +## License + +Licensed under either of + + * [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0) + * [MIT license](http://opensource.org/licenses/MIT) + +at your option. + +### Contribution + +Unless you explicitly state otherwise, any contribution intentionally submitted +for inclusion in the work by you, as defined in the Apache-2.0 license, shall be +dual licensed as above, without any additional terms or conditions. + diff --git a/vrf/src/error.rs b/vrf/src/error.rs new file mode 100644 index 00000000..11fca1f1 --- /dev/null +++ b/vrf/src/error.rs @@ -0,0 +1,54 @@ +//! VRF error types +//! +//! This module defines error handling types for Verifiable Random Function (VRF) +//! operations. The error type is intentionally minimal to prevent potential +//! side-channel leaks that could compromise the security of VRF-related +//! cryptographic operations. + +use core::{error, fmt}; + +/// Result type. +/// +/// A specialized result type alias for VRF operations, using the [`Error`] type +/// defined in this module. +pub type Result = core::result::Result; + +/// VRF errors. +/// +/// This type represents errors that may occur during VRF operations. It is +/// designed to be opaque to avoid exposing internal details that could be +/// exploited in cryptographic attacks. Currently, it does not include a source +/// field, but it is marked as `non_exhaustive` to allow for future extensions. +#[derive(Default)] +#[non_exhaustive] +pub struct Error {} + +impl Error { + /// Creates a new VRF error. + fn new() -> Self { + Self::default() + } +} + +impl fmt::Debug for Error { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str("vrf::Error {}") + } +} + +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.write_str("vrf::Error {}") + } +} + +impl error::Error for Error { + /// Returns the source of the error, if any. + /// + /// Since this implementation does not currently support a source, this + /// method always returns `None`. This behavior may change in future + /// iterations if the error type is extended. + fn source(&self) -> Option<&(dyn core::error::Error + 'static)> { + None + } +} diff --git a/vrf/src/keypair.rs b/vrf/src/keypair.rs new file mode 100644 index 00000000..c609238d --- /dev/null +++ b/vrf/src/keypair.rs @@ -0,0 +1,21 @@ +//! Cryptographic keypairs for VRF operations. +//! +//! This module defines traits for working with keypairs in the context of +//! Verifiable Random Functions (VRFs). A keypair consists of a proving key +//! (used to generate VRF outputs) and a verifying key (used to verify those +//! outputs). + +/// VRF keypair with an associated verifying key. +/// +/// Implementors of this trait must provide access to +/// the verifying key, which can be used to validate VRF outputs produced by +/// the proving key. +pub trait Keypair { + /// This associated type defines the specific type of the verifying key, + /// which must implement [`Clone`] to allow for safe duplication when + /// retrieved. + type VerifyingKey: Clone; + + /// Returns the verifying key. + fn verifying_key(&self) -> Self::VerifyingKey; +} diff --git a/vrf/src/lib.rs b/vrf/src/lib.rs new file mode 100644 index 00000000..3846466d --- /dev/null +++ b/vrf/src/lib.rs @@ -0,0 +1,73 @@ +//! Verifiable Random Function (VRF) traits +//! +//! This module defines core traits for implementing Verifiable Random Functions. +//! A VRF allows a prover to generate an unforgeable proof for a value that can be +//! verified by anyone who has the corresponding verification key. +//! +//! The three main traits defined here are: +//! - [`Proof`]: Represents a VRF proof that can be converted to a hash output +//! - [`Prover`]: Represents VRF proof generator +//! - [`Verifier`]: Represents VRF proof verifier + +#![no_std] + +mod error; +mod keypair; + +use digest::{Output, OutputSizeUser}; + +/// VRF proof representation. +/// +/// This trait defines the interface for VRF proofs. Proofs can be transformed +/// into hash outputs of a specific hash algorithm `H`. +pub trait Proof +where + H: OutputSizeUser, +{ + /// Converts a proof to its corresponding hash output. + fn proof_to_hash(&self) -> Output; +} + +/// VRF prover. +/// +/// Implementers of this trait can generate verifiable random function proofs +/// for arbitrary input challenges. The prover uses secret key to +/// produce outputs that can later be verified by parties with the corresponding +/// verification key. +pub trait Prover +where + H: OutputSizeUser, +{ + /// The specific proof type produced by this prover. + type Proof: Proof; + + /// Generates a VRF proof for the given input challenge. + /// + /// # Parameters + /// * `alpha` - The input challenge/message bytes for which to generate a proof + /// + /// # Returns + /// A Result containing either the generated proof or an error if proof generation fails. + fn prove(&self, alpha: &[u8]) -> error::Result; +} + +/// VRF verifier. +/// +/// Implementers of this trait can verify VRF proofs for the given input. +pub trait Verifier +where + H: OutputSizeUser, +{ + /// The specific proof type this verifier can check. + type Proof: Proof; + + /// Verifies a VRF proof for an input challenge. + /// + /// # Parameters + /// * `alpha` - The original input challenge/message bytes + /// * `proof` - The proof to verify + /// + /// # Returns + /// A Result containing either the hash output (if verification succeeds) or an error. + fn verify(&self, alpha: &[u8], proof: Self::Proof) -> error::Result>; +}