eyvara-vrf

What is a VRF

A verifiable random function (VRF) lets a secret-key holder compute a deterministic pseudorandom output for an input and publish a proof that anyone can verify with the corresponding public key. For a fixed secret key and input, the output is unique; without the secret key, it should be computationally infeasible to predict the output before seeing a valid proof.

Security Notice

Known limitations: infinity_norm is not constant-time, and the rejection sampling loop has input-dependent timing. Do not use in systems where side-channel resistance is required.

Quick Start

use eyvara::{eyvara_eval, eyvara_keygen, eyvara_verify, EyvaraError};
use eyvara::params::EYVARA_128;
use rand::rngs::OsRng;

fn main() -> Result<(), EyvaraError> {
    let mut rng = OsRng;
    let (pk, sk) = eyvara_keygen(&EYVARA_128, &mut rng);
    let input = b"my application input";
    let (output, proof) = eyvara_eval(&EYVARA_128, &sk, input)?;
    let valid = eyvara_verify(&EYVARA_128, &pk, input, &output, &proof)?;
    assert!(valid);
    Ok(())
}

Parameter Sets

Name	Security	Proof Size	Key Size
EYVARA_128	NIST Cat. 1 (~128-bit classical)	~1.3 KB	~4 KB public, ~8 KB secret
EYVARA_192	NIST Cat. 3 (~192-bit classical)	~2.0 KB	~6 KB public, ~12 KB secret

Optional Features

The serde feature enables Serialize and Deserialize for PublicKey, EyvaraProof, and EyvaraOutput. SecretKey supports Serialize only; reconstruction is available from trusted serialized components, but untrusted key import is not provided by this crate.

eyvara-vrf = { version = "0.1", features = ["serde"] }

Building, Testing, Benchmarking

cargo build --release
cargo test
cargo test --doc
cargo test --features serde
cargo bench

License

MIT OR Apache-2.0

eyvara-vrf 0.1.0