Crate lamport_signature_plus 

Implementation of Lamport’s one-time signature scheme.

Usage

use lamport_signature_plus::{VerifyingKey, SigningKey, LamportFixedDigest};
use sha2::Sha256;
use rand_chacha::{ChaChaRng, rand_core::SeedableRng};

let mut rng = ChaChaRng::from_rng(&mut rand::rng());
let mut signing_key = SigningKey::<LamportFixedDigest<Sha256>>::random(rng);
let verifying_key = VerifyingKey::from(&signing_key);
let signature = signing_key.sign(b"Hello, World!").expect("signing failed");
assert!(verifying_key.verify(&signature, b"Hello, World!").is_ok());

Digest algorithms

SigningKey and VerifyingKey accept hash functions provided by RustCrypto/hashes. Use LamportFixedDigest for fixed-output functions or LamportExtendableDigest for extendable-output functions. Extendable-output functions use a 64-byte output.

Extendable-output example

use lamport_signature_plus::{VerifyingKey, SigningKey, LamportExtendableDigest};
use shake::Shake128;
use rand_chacha::{ChaChaRng, rand_core::SeedableRng};

let mut rng = ChaChaRng::from_rng(&mut rand::rng());
let mut signing = SigningKey::<LamportExtendableDigest<Shake128>>::random(rng);
let verifying = VerifyingKey::from(&signing);
let signature = signing.sign(b"Hello, World!").expect("signing failed");
assert!(verifying.verify(&signature, b"Hello, World!").is_ok());

Random number generators

SigningKey requires a cryptographically secure random number generator that implements CryptoRng.

Note

A SigningKey can securely sign only one message. Attempting to sign with a used key returns an error.

Merkle-tree Lamport signatures

MtSigningKey commits 2, 4, or 8 one-time Lamport public keys in a Merkle tree. Its compact MtVerifyingKey is only the tree depth and root. Each MtSignature carries its leaf public key and authentication path.

use lamport_signature_plus::{LamportFixedDigest, generate_mt_keys};
use rand::SeedableRng;
use rand_chacha::ChaCha8Rng;
use sha2::Sha256;

let mut rng = ChaCha8Rng::from_seed([7; 32]);
let (mut signing_key, verifying_key) =
    generate_mt_keys::<LamportFixedDigest<Sha256>, _>(2, &mut rng)?;

let signature = signing_key.sign(b"first message")?;
assert_eq!(signature.index(), 0);
verifying_key.verify(&signature, b"first message")?;

The MT signing key is stateful. Persist its updated state after every signature; restoring an older copy can reuse a Lamport leaf and destroy security. Each signing operation destroys the consumed leaf secret, so the canonical signing-key state becomes smaller as indices are consumed.

Structs

LamportExtendableDigest

A Lamport signature scheme that uses extendable-output functions.

LamportFixedDigest

A Lamport signature scheme that uses fixed-output functions.

MtSignature

A Lamport signature bundled with its leaf public key and Merkle authentication path.

MtSignatureShare

A participant’s threshold signature share with its Merkle inclusion proof.

MtSigningKey

A stateful collection of Lamport one-time signing keys committed by a Merkle tree.

MtSigningKeyShare

One participant’s threshold shares for the unused MT-Lamport leaves.

MtVerifyingKey

A compact Merkle root that verifies up to eight Lamport one-time signatures.

MultiVec

A multidimensional vector that is faster and simpler than Vec<Vec<T>>.

Signature

A signature generated by SigningKey.

SignatureShare

A signature share generated by SigningKeyShare.

SigningKey

A one-time signing private key.

SigningKeyShare

A key share used to reconstruct a signing key or create a partial signature.

VerifyingKey

A one-time signing public key.

Enums

LamportError

Errors produced by the Lamport signature scheme.

Traits

LamportDigest

Digest operations required by the Lamport signature scheme.

Functions

generate_keys

Generate a new key pair.

generate_mt_keys

Generate a stateful Merkle-tree Lamport key pair.

Type Aliases

LamportResult

Result type for Lamport errors.