Struct Signature

pub struct Signature { /* private fields */ }

An RPO Falcon512 signature over a message.

The signature is a pair of polynomials (s1, s2) in (Z_p[x]/(phi))^2 a nonce r, and a public key polynomial h where:

• p := 12289
• phi := x^512 + 1

The signature verifies against a public key pk if and only if:

1. s1 = c - s2 * h
2. |s1|^2 + |s2|^2 <= SIG_L2_BOUND

where |.| is the norm and:

• c = HashToPoint(r || message)
• pk = Rpo256::hash(h)

Here h is a polynomial representing the public key and pk is its digest using the Rpo256 hash function. c is a polynomial that is the hash-to-point of the message being signed.

The polynomial h is serialized as:

1. 1 byte representing the log2(512) i.e., 9.
2. 896 bytes for the public key itself.

The signature is serialized as:

1. A header byte specifying the algorithm used to encode the coefficients of the s2 polynomial together with the degree of the irreducible polynomial phi. For RPO Falcon512, the header byte is set to 10111001 which differentiates it from the standardized instantiation of the Falcon signature.
2. 40 bytes for the nonce.
3. 625 bytes encoding the s2 polynomial above.

The total size of the signature (including the extended public key) is 1563 bytes.

Implementations

impl Signature

pub fn new(nonce: Nonce, h: PubKeyPoly, s2: SignaturePoly) -> Signature

pub fn pk_poly(&self) -> &PubKeyPoly

Returns the public key polynomial h.

pub fn sig_poly(&self) -> &Polynomial<FalconFelt>

pub fn nonce(&self) -> &Nonce

Returns the nonce component of the signature.

pub fn verify(&self, message: Word, pubkey_com: Word) -> bool

Returns true if this signature is a valid signature for the specified message generated against the secret key matching the specified public key commitment.

Trait Implementations

impl Clone for Signature

fn clone(&self) -> Signature

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Signature

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

Formats the value using the given formatter.

impl Deserializable for Signature

fn read_from<R: ByteReader>( source: &mut R, ) -> Result<Self, DeserializationError>

Reads a sequence of bytes from the provided source, attempts to deserialize these bytes into Self, and returns the result.

fn read_from_bytes(bytes: &[u8]) -> Result<Self, DeserializationError>

Attempts to deserialize the provided bytes into Self and returns the result.

impl PartialEq for Signature

fn eq(&self, other: &Signature) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serializable for Signature

fn write_into<W: ByteWriter>(&self, target: &mut W)

Serializes self into bytes and writes these bytes into the target.

fn to_bytes(&self) -> Vec<u8>

Serializes self into a vector of bytes.

fn get_size_hint(&self) -> usize

Returns an estimate of how many bytes are needed to represent self.

impl Eq for Signature

impl StructuralPartialEq for Signature