Struct jubjub::AffinePoint

pub struct AffinePoint { /* private fields */ }

This represents a Jubjub point in the affine (u, v) coordinates.

Implementations

impl AffinePoint

pub const fn identity() -> Self

Constructs the neutral element (0, 1).

pub fn is_identity(&self) -> Choice

Determines if this point is the identity.

pub fn mul_by_cofactor(&self) -> ExtendedPoint

Multiplies this point by the cofactor, producing an ExtendedPoint

pub fn is_small_order(&self) -> Choice

Determines if this point is of small order.

pub fn is_torsion_free(&self) -> Choice

Determines if this point is torsion free and so is in the prime order subgroup.

pub fn is_prime_order(&self) -> Choice

Determines if this point is prime order, or in other words that the smallest scalar multiplied by this point that produces the identity is r. This is equivalent to checking that the point is both torsion free and not the identity.

pub fn to_bytes(&self) -> [u8; 32]

Converts this element into its byte representation.

pub fn from_bytes(b: [u8; 32]) -> CtOption<Self>

Attempts to interpret a byte representation of an affine point, failing if the element is not on the curve or non-canonical.

pub fn from_bytes_pre_zip216_compatibility(b: [u8; 32]) -> CtOption<Self>

Attempts to interpret a byte representation of an affine point, failing if the element is not on the curve.

Most non-canonical encodings will also cause a failure. However, this API preserves (for use in consensus-critical protocols) a bug in the parsing code that caused two non-canonical encodings to be silently accepted:

• (0, 1), which is the identity;
• (0, -1), which is a point of order two.

Each of these has a single non-canonical encoding in which the value of the sign bit is 1.

See ZIP 216 for a more detailed description of the bug, as well as its fix.

pub fn batch_from_bytes(
    items: impl Iterator<Item = [u8; 32]>
) -> Vec<CtOption<Self>>

Attempts to interpret a batch of byte representations of affine points.

Returns None for each element if it is not on the curve, or is non-canonical according to ZIP 216.

pub fn get_u(&self) -> Fq

Returns the u-coordinate of this point.

pub fn get_v(&self) -> Fq

Returns the v-coordinate of this point.

pub const fn to_extended(&self) -> ExtendedPoint

Returns an ExtendedPoint for use in arithmetic operations.

pub const fn to_niels(&self) -> AffineNielsPoint

Performs a pre-processing step that produces an AffineNielsPoint for use in multiple additions.

pub const fn from_raw_unchecked(u: Fq, v: Fq) -> AffinePoint

Constructs an AffinePoint given u and v without checking that the point is on the curve.

Trait Implementations

impl<'a, 'b> Add<&'b AffinePoint> for &'a ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the + operator.

fn add(self, other: &'b AffinePoint) -> ExtendedPoint

Performs the + operation.

impl<'b> Add<&'b AffinePoint> for ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the + operator.

fn add(self, rhs: &'b AffinePoint) -> ExtendedPoint

Performs the + operation.

impl<'a> Add<AffinePoint> for &'a ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the + operator.

fn add(self, rhs: AffinePoint) -> ExtendedPoint

Performs the + operation.

impl Add<AffinePoint> for ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the + operator.

fn add(self, rhs: AffinePoint) -> ExtendedPoint

Performs the + operation.

impl<'b> AddAssign<&'b AffinePoint> for ExtendedPoint

fn add_assign(&mut self, rhs: &'b AffinePoint)

Performs the += operation.

impl AddAssign<AffinePoint> for ExtendedPoint

fn add_assign(&mut self, rhs: AffinePoint)

Performs the += operation.

impl Clone for AffinePoint

fn clone(&self) -> AffinePoint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl CofactorCurveAffine for AffinePoint

type Scalar = Fr

type Curve = ExtendedPoint

fn identity() -> Self

Returns the additive identity.

fn generator() -> Self

Returns a fixed generator of unknown exponent.

fn is_identity(&self) -> Choice

Determines if this point represents the point at infinity; the additive identity.

fn to_curve(&self) -> Self::Curve

Converts this element to its curve representation.

impl ConditionallySelectable for AffinePoint

fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self

Select a or b according to choice.

fn conditional_assign(&mut self, other: &Self, choice: Choice)

Conditionally assign other to self, according to choice.

fn conditional_swap(a: &mut Self, b: &mut Self, choice: Choice)

Conditionally swap self and other if choice == 1; otherwise, reassign both unto themselves.

impl ConstantTimeEq for AffinePoint

fn ct_eq(&self, other: &Self) -> Choice

Determine if two items are equal.

impl Debug for AffinePoint

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

Formats the value using the given formatter.

impl Default for AffinePoint

fn default() -> AffinePoint

Returns the identity.

impl Display for AffinePoint

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

Formats the value using the given formatter.

impl<'a> From<&'a ExtendedPoint> for AffinePoint

fn from(extended: &'a ExtendedPoint) -> AffinePoint

Constructs an affine point from an extended point using the map (U, V, Z, T1, T2) => (U/Z, V/Z) as Z is always nonzero. This requires a field inversion and so it is recommended to perform these in a batch using batch_normalize instead.

impl From<AffinePoint> for ExtendedPoint

fn from(affine: AffinePoint) -> ExtendedPoint

Constructs an extended point (with Z = 1) from an affine point using the map (u, v) => (u, v, 1, u, v).

impl From<ExtendedPoint> for AffinePoint

fn from(extended: ExtendedPoint) -> AffinePoint

Converts to this type from the input type.

impl GroupEncoding for AffinePoint

type Repr = [u8; 32]

The encoding of group elements.

fn from_bytes(bytes: &Self::Repr) -> CtOption<Self>

Attempts to deserialize a group element from its encoding.

fn from_bytes_unchecked(bytes: &Self::Repr) -> CtOption<Self>

Attempts to deserialize a group element, not checking if the element is valid.

fn to_bytes(&self) -> Self::Repr

Converts this element into its byte encoding. This may or may not support encoding the identity.

impl<'a, 'b> Mul<&'b Fr> for &'a AffinePoint

type Output = ExtendedPoint

The resulting type after applying the * operator.

fn mul(self, other: &'b Fr) -> ExtendedPoint

Performs the * operation.

impl<'b> Mul<&'b Fr> for AffinePoint

type Output = ExtendedPoint

The resulting type after applying the * operator.

fn mul(self, rhs: &'b Fr) -> ExtendedPoint

Performs the * operation.

impl<'a> Mul<Fr> for &'a AffinePoint

type Output = ExtendedPoint

The resulting type after applying the * operator.

fn mul(self, rhs: Fr) -> ExtendedPoint

Performs the * operation.

impl Mul<Fr> for AffinePoint

type Output = ExtendedPoint

The resulting type after applying the * operator.

fn mul(self, rhs: Fr) -> ExtendedPoint

Performs the * operation.

impl Neg for AffinePoint

fn neg(self) -> AffinePoint

This computes the negation of a point P = (u, v) as -P = (-u, v).

type Output = AffinePoint

The resulting type after applying the - operator.

impl PartialEq<AffinePoint> for AffinePoint

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl<'a, 'b> Sub<&'b AffinePoint> for &'a ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the - operator.

fn sub(self, other: &'b AffinePoint) -> ExtendedPoint

Performs the - operation.

impl<'b> Sub<&'b AffinePoint> for ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the - operator.

fn sub(self, rhs: &'b AffinePoint) -> ExtendedPoint

Performs the - operation.

impl<'a> Sub<AffinePoint> for &'a ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the - operator.

fn sub(self, rhs: AffinePoint) -> ExtendedPoint

Performs the - operation.

impl Sub<AffinePoint> for ExtendedPoint

type Output = ExtendedPoint

The resulting type after applying the - operator.

fn sub(self, rhs: AffinePoint) -> ExtendedPoint

Performs the - operation.

impl<'b> SubAssign<&'b AffinePoint> for ExtendedPoint

fn sub_assign(&mut self, rhs: &'b AffinePoint)

Performs the -= operation.

impl SubAssign<AffinePoint> for ExtendedPoint

fn sub_assign(&mut self, rhs: AffinePoint)

Performs the -= operation.

impl Copy for AffinePoint

impl Eq for AffinePoint

impl StructuralEq for AffinePoint