Struct QIndexedSignatureScheme 

pub struct QIndexedSignatureScheme { /* private fields */ }

The q-indexed signature scheme, as described in Section 14.6.1 in the textbook by Boneh & Shoup.

It instantiates q one-time signatures schemes (currently WinternitzSignatureScheme) and uses it to sign up to q messages. To shrink the public key to a single hash, a MerkleTree is used: The signatures contains the one-time public key that was used, along with a Merkle proof.

Examples

use hash_based_signatures::signature::q_indexed_signature::QIndexedSignatureScheme;
use hash_based_signatures::signature::SignatureScheme;
use hash_based_signatures::signature::winternitz::d::D;

let mut signature_scheme = QIndexedSignatureScheme::new(2, [0; 32], D::new(255));
let signature0 = signature_scheme.sign((0, [0u8; 32]));
let signature1 = signature_scheme.sign((1, [1u8; 32]));

assert!(QIndexedSignatureScheme::verify(
    signature_scheme.public_key(),
    (0, [0u8; 32]),
    &signature0
));
assert!(QIndexedSignatureScheme::verify(
    signature_scheme.public_key(),
    (1, [1u8; 32]),
    &signature1
));

Implementations

impl QIndexedSignatureScheme

pub fn new(q: usize, seed: [u8; 32], d: D) -> Self

Builds a q-indexed signature scheme from the given seed.

Panics

Panics if q is not a power of two.

Trait Implementations

impl Clone for QIndexedSignatureScheme

fn clone(&self) -> QIndexedSignatureScheme

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl SignatureScheme<[u8; 32], (usize, [u8; 32]), QIndexedSignature> for QIndexedSignatureScheme

fn sign(&mut self, message: (usize, HashType)) -> QIndexedSignature

Signs a message.

Panics

Panics if the scheme is used more than once to sign different messages with the same index. Note that there could still be a different instance with the same secret key, which would not be detected.

fn public_key(&self) -> HashType

Returns a copy of the public key

fn verify( pk: HashType, message: (usize, HashType), signature: &QIndexedSignature, ) -> bool

Verifies a signature. Note that this function does not require need self, hence does not need an instance of the signature scheme. This is because an instance of a signature scheme contains the signing key which is typically not available for the verifier.