Struct elastic_elgamal::ProofOfPossession

pub struct ProofOfPossession<G: Group> { /* private fields */ }

Zero-knowledge proof of possession of one or more secret scalars.

Construction

The proof is a generalization of the standard Schnorr protocol for proving knowledge of a discrete log. The difference with the combination of several concurrent Schnorr protocol instances is that the challenge is shared among all instances (which yields a ~2x proof size reduction).

Implementation notes

• Proof generation is constant-time. Verification is not constant-time.

Examples

let mut rng = thread_rng();
let keypairs: Vec<_> =
    (0..5).map(|_| Keypair::<Ristretto>::generate(&mut rng)).collect();

// Prove possession of the generated key pairs.
let proof = ProofOfPossession::new(
    &keypairs,
    &mut Transcript::new(b"custom_proof"),
    &mut rng,
);
proof.verify(
    keypairs.iter().map(Keypair::public),
    &mut Transcript::new(b"custom_proof"),
)?;

// If we change the context of the `Transcript`, the proof will not verify.
assert!(proof
    .verify(
        keypairs.iter().map(Keypair::public),
        &mut Transcript::new(b"other_proof"),
    )
    .is_err());
// Likewise if the public keys are reordered.
assert!(proof
    .verify(
        keypairs.iter().rev().map(Keypair::public),
        &mut Transcript::new(b"custom_proof"),
    )
    .is_err());

Implementations

impl<G: Group> ProofOfPossession<G>

pub fn new<R: CryptoRng + RngCore>( keypairs: &[Keypair<G>], transcript: &mut Transcript, rng: &mut R ) -> Self

Creates a proof of possession with the specified keypairs.

pub fn verify<'a>( &self, public_keys: impl Iterator<Item = &'a PublicKey<G>> + Clone, transcript: &mut Transcript ) -> Result<(), VerificationError>

Verifies this proof against the provided public_keys.

Errors

Returns an error if this proof does not verify.

Trait Implementations

impl<G: Clone + Group> Clone for ProofOfPossession<G>

where G::Scalar: Clone,

fn clone(&self) -> ProofOfPossession<G>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<G: Debug + Group> Debug for ProofOfPossession<G>

where G::Scalar: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de, G: Group> Deserialize<'de> for ProofOfPossession<G>

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<G: Group> Serialize for ProofOfPossession<G>

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.