Trait frost_core::Field

pub trait Field: Copy + Clone {
    type Scalar: Add<Output = Self::Scalar> + Copy + Clone + Eq + Mul<Output = Self::Scalar> + PartialEq + Sub<Output = Self::Scalar>;
    type Serialization: AsRef<[u8]> + Debug + TryFrom<Vec<u8>>;

    // Required methods
    fn zero() -> Self::Scalar;
    fn one() -> Self::Scalar;
    fn invert(scalar: &Self::Scalar) -> Result<Self::Scalar, FieldError>;
    fn random<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar;
    fn serialize(scalar: &Self::Scalar) -> Self::Serialization;
    fn little_endian_serialize(scalar: &Self::Scalar) -> Self::Serialization;
    fn deserialize(
        buf: &Self::Serialization
    ) -> Result<Self::Scalar, FieldError>;
}

A prime order finite field GF(q) over which all scalar values for our prime order group can be multiplied are defined.

This trait does not have to be implemented for a finite field scalar itself, it can be a pass-through, implemented for a type just for the ciphersuite, and calls through to another implementation underneath, so that this trait does not have to be implemented for types you don’t own.

Required Associated Types

type Scalar: Add<Output = Self::Scalar> + Copy + Clone + Eq + Mul<Output = Self::Scalar> + PartialEq + Sub<Output = Self::Scalar>

An element of the scalar field GF(p). The Eq/PartialEq implementation MUST be constant-time.

type Serialization: AsRef<[u8]> + Debug + TryFrom<Vec<u8>>

A unique byte array buf of fixed length N.

Required Methods

fn zero() -> Self::Scalar

Returns the zero element of the field, the additive identity.

fn one() -> Self::Scalar

Returns the one element of the field, the multiplicative identity.

fn invert(scalar: &Self::Scalar) -> Result<Self::Scalar, FieldError>

Computes the multiplicative inverse of an element of the scalar field, failing if the element is zero.

fn random<R: RngCore + CryptoRng>(rng: &mut R) -> Self::Scalar

Generate a random scalar from the entire space [0, l-1]

https://www.ietf.org/archive/id/draft-irtf-cfrg-frost-11.html#section-3.1-3.3

fn serialize(scalar: &Self::Scalar) -> Self::Serialization

A member function of a Field that maps a Scalar to a unique byte array buf of fixed length Ne.

https://www.ietf.org/archive/id/draft-irtf-cfrg-frost-11.html#section-3.1-3.8

fn little_endian_serialize(scalar: &Self::Scalar) -> Self::Serialization

A member function of a Field that maps a Scalar to a unique byte array buf of fixed length Ne, in little-endian order.

This is used internally.

fn deserialize(buf: &Self::Serialization) -> Result<Self::Scalar, FieldError>

A member function of a Field that attempts to map a byte array buf to a Scalar.

Fails if the input is not a valid byte representation of an Scalar of the Field. This function can raise an Error if deserialization fails or if the resulting Scalar is zero

https://www.ietf.org/archive/id/draft-irtf-cfrg-frost-11.html#section-3.1-3.9

Implementors