Trait ScalarOps

pub trait ScalarOps {
    type Scalar: Copy + Default + From<u64> + From<Self::Scalar> + Neg<Output = Self::Scalar> + Add<Output = Self::Scalar> + for<'a> Add<&'a Self::Scalar, Output = Self::Scalar> + Sub<Output = Self::Scalar> + Mul<Output = Self::Scalar> + for<'a> Mul<&'a Self::Scalar, Output = Self::Scalar> + PartialEq + Zeroize + Debug;

    const SCALAR_SIZE: usize;

    // Required methods
    fn generate_scalar<R: CryptoRng + RngCore>(rng: &mut R) -> Self::Scalar;
    fn invert_scalar(scalar: Self::Scalar) -> Self::Scalar;
    fn serialize_scalar(scalar: &Self::Scalar, buffer: &mut [u8]);
    fn deserialize_scalar(buffer: &[u8]) -> Option<Self::Scalar>;

    // Provided methods
    fn scalar_from_random_bytes(source: RandomBytesProvider<'_>) -> Self::Scalar { ... }
    fn invert_scalars(scalars: &mut [Self::Scalar]) { ... }
}

Helper trait for Group that describes operations on group scalars.

Required Associated Constants

const SCALAR_SIZE: usize

Byte size of a serialized Self::Scalar.

Required Associated Types

type Scalar: Copy + Default + From<u64> + From<Self::Scalar> + Neg<Output = Self::Scalar> + Add<Output = Self::Scalar> + for<'a> Add<&'a Self::Scalar, Output = Self::Scalar> + Sub<Output = Self::Scalar> + Mul<Output = Self::Scalar> + for<'a> Mul<&'a Self::Scalar, Output = Self::Scalar> + PartialEq + Zeroize + Debug

Scalar type. As per Group contract, scalars must form a prime field. Arithmetic operations on scalars requested here must be constant-time.

Required Methods

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

Generates a random scalar based on the provided CSPRNG. This operation must be constant-time.

fn invert_scalar(scalar: Self::Scalar) -> Self::Scalar

Inverts the scalar, which is guaranteed to be non-zero. This operation does not need to be constant-time.

fn serialize_scalar(scalar: &Self::Scalar, buffer: &mut [u8])

Serializes the scalar into the provided buffer, which is guaranteed to have length Self::SCALAR_SIZE.

fn deserialize_scalar(buffer: &[u8]) -> Option<Self::Scalar>

Deserializes the scalar from buffer, which is guaranteed to have length Self::SCALAR_SIZE. This method returns None if the buffer does not correspond to a representation of a valid scalar.

Provided Methods

fn scalar_from_random_bytes(source: RandomBytesProvider<'_>) -> Self::Scalar

Generates a scalar from a source of random bytes. This operation must be constant-time. The source is guaranteed to return any necessary number of bytes.

Default implementation

1. Create a ChaCha RNG using 32 bytes read from source as the seed.
2. Call Self::generate_scalar() with the created RNG.

fn invert_scalars(scalars: &mut [Self::Scalar])

Inverts scalars in a batch. This operation does not need to be constant-time.

Default implementation

Inverts every scalar successively.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl ScalarOps for Curve25519Subgroup

const SCALAR_SIZE: usize = 32usize

type Scalar = Scalar

impl ScalarOps for Ristretto

const SCALAR_SIZE: usize = 32usize

type Scalar = Scalar

impl<C> ScalarOps for Generic<C>

where C: CurveArithmetic, Scalar<C>: Zeroize,

const SCALAR_SIZE: usize = <FieldBytesSize<C> as Unsigned>::USIZE

type Scalar = <C as CurveArithmetic>::Scalar