Crate rfc6979

RustCrypto: RFC6979 Deterministic Signatures

Pure Rust implementation of RFC6979: Deterministic Usage of the Digital Signature Algorithm (DSA) and Elliptic Curve Digital Signature Algorithm (ECDSA).

Algorithm described in RFC 6979 § 3.2: https://tools.ietf.org/html/rfc6979#section-3

Documentation

Minimum Supported Rust Version

This crate requires Rust 1.57 at a minimum.

We may change the MSRV in the future, but it will be accompanied by a minor version bump.

License

All crates licensed under either of

• Apache License, Version 2.0
• MIT license

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.

Usage

See also: the documentation for the generate_k function.

use crypto_bigint::{ArrayEncoding, U256};
use sha2::{Digest, Sha256};

// NIST P-256 field modulus
const NIST_P256_MODULUS: U256 =
    U256::from_be_hex("FFFFFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632551");

// Public key for RFC6979 NIST P256/SHA256 test case
const RFC6979_KEY: U256 =
    U256::from_be_hex("C9AFA9D845BA75166B5C215767B1D6934E50C3DB36E89B127B8A622B120F6721");

// Test message for RFC6979 NIST P256/SHA256 test case
const RFC6979_MSG: &[u8; 6] = b"sample";

// Expected K for RFC6979 NIST P256/SHA256 test case
const RFC6979_EXPECTED_K: U256 =
    U256::from_be_hex("A6E3C57DD01ABE90086538398355DD4C3B17AA873382B0F24D6129493D8AAD60");

let h = Sha256::digest(RFC6979_MSG);
let aad = b"";
let k = rfc6979::generate_k::<Sha256, U256>(&RFC6979_KEY, &NIST_P256_MODULUS, &h, aad);
assert_eq!(&k.to_be_byte_array(), &RFC6979_EXPECTED_K.to_be_byte_array());

Structs

• HmacDrbg
  Internal implementation of HMAC_DRBG as described in NIST SP800-90A.

Functions

• generate_k
  Deterministically generate ephemeral scalar k.