Struct FieldElement 

pub struct FieldElement(/* private fields */);

P-521 field element representing values in Fₚ (p = 2^521 − 1). Internally stored as 17 little-endian 32-bit limbs; only the low 9 bits of limb 16 are significant.

Implementations

impl FieldElement

pub fn zero() -> Self

The additive identity element: 0

pub fn one() -> Self

The multiplicative identity element: 1

impl FieldElement

pub fn from_bytes(bytes: &[u8; 66]) -> Result<Self>

Create a field element from big-endian byte representation.

Validates that the input represents a value less than the field modulus p. Returns an error if the value is >= p.

pub fn to_bytes(&self) -> [u8; 66]

Convert field element to big-endian byte representation

pub fn is_zero(&self) -> bool

Check if the field element represents zero

pub fn is_odd(&self) -> bool

Return true if the field element is odd (least-significant bit set)

pub fn is_valid(&self) -> bool

self < p ? (constant-time)

impl FieldElement

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

Constant-time conditional swap

Swaps the two field elements if choice is 1, leaves them unchanged if choice is 0. This operation is performed in constant time to prevent timing attacks.

impl FieldElement

pub fn add(&self, other: &Self) -> Self

Constant-time addition modulo p

pub fn sub(&self, other: &Self) -> Self

Constant-time subtraction modulo p

pub fn mul(&self, other: &Self) -> Self

Field multiplication using school-book multiply + Mersenne reduction.

pub fn square(&self) -> Self

Field squaring – just a specialised multiplication.

pub fn invert(&self) -> Result<Self>

Fermat-inversion a^(p−2) via left-to-right square-and-multiply.

pub fn sqrt(&self) -> Option<Self>

Square-root via a^{(p+1)/4} (because p ≡ 3 mod 4). (p+1)/4 = 2^519.

Trait Implementations

impl Clone for FieldElement

fn clone(&self) -> FieldElement

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FieldElement

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

Formats the value using the given formatter.

impl PartialEq for FieldElement

fn eq(&self, other: &FieldElement) -> 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 Zeroize for FieldElement

fn zeroize(&mut self)

Zero out this object from memory using Rust intrinsics which ensure the zeroization operation is not “optimized away” by the compiler.

impl Eq for FieldElement

impl StructuralPartialEq for FieldElement