Enum BigIntError 

#[non_exhaustive]
pub enum BigIntError {
    Overflow,
    InvalidEncoding,
    DivisionByZero,
    InvalidModulus,
    InvalidState,
}

Errors that can occur during BigInt operations.

All variants are designed to be constant-time and provide minimal information to prevent side-channel attacks while still being useful for debugging.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Overflow

Operation would exceed the maximum capacity.

This error occurs when a BigInt operation would require more limbs than the configured maximum capacity. This prevents unbounded memory allocation and ensures constant-time behavior.

Examples

use clock_bigint::{BigInt, add_magnitude};

// Create BigInts with values that need 1 limb each
let a = BigInt::from_u64(u64::MAX, 10);
let b = BigInt::from_u64(u64::MAX, 10);

// Try to add into a result with insufficient capacity (only 1 limb max)
let mut result = BigInt::new(1); // Only 1 limb capacity
let add_result = add_magnitude(&a, &b, &mut result);
assert!(add_result.is_err());

InvalidEncoding

Invalid encoding detected (non-canonical form).

This error occurs when attempting to decode malformed or non-canonical binary representations of BigInt values. The encoding format requires specific structure and canonical forms for security and correctness.

Examples

use clock_bigint::BigInt;

// Empty data cannot be decoded
let result = clock_bigint::decode(&[]);
assert!(matches!(result, Err(clock_bigint::BigIntError::InvalidEncoding)));

// Invalid length prefix
let invalid_data = vec![0u8; 10]; // Too short for valid encoding
let result = clock_bigint::decode(&invalid_data);
assert!(matches!(result, Err(clock_bigint::BigIntError::InvalidEncoding)));

DivisionByZero

Division by zero attempted.

This error occurs when attempting to divide by zero or compute modulo zero. These operations are mathematically undefined.

Examples

use clock_bigint::{BigInt, div};

let a = BigInt::from_u64(10, 10);
let zero = BigInt::from_u64(0, 10);

// Division by zero
let result = div(&a, &zero);
assert!(matches!(result, Err(clock_bigint::BigIntError::DivisionByZero)));

InvalidModulus

Invalid modulus for Montgomery arithmetic.

This error occurs when attempting to use Montgomery arithmetic with an unsupported modulus. Montgomery operations require the modulus to be odd and non-zero for the algorithms to work correctly.

Examples

use clock_bigint::{BigInt, MontgomeryContext};

let even_modulus = BigInt::from_u64(10, 10); // Even modulus

// Creating Montgomery context with even modulus fails
let result = MontgomeryContext::new(even_modulus);
assert!(matches!(result, Err(clock_bigint::BigIntError::InvalidModulus)));

let zero_modulus = BigInt::from_u64(0, 10); // Zero modulus
let result = MontgomeryContext::new(zero_modulus);
assert!(matches!(result, Err(clock_bigint::BigIntError::InvalidModulus)));

InvalidState

Invalid internal state.

This error occurs when an operation is attempted but the BigInt is in an invalid internal state, such as having non-canonical representation when canonical form is required.

Examples

use clock_bigint::BigInt;

let mut bi = BigInt::from_u64(10, 10);
// Manually corrupt internal state (normally not possible through public API)
// This would cause InvalidState if the corruption were detected

Trait Implementations

impl Clone for BigIntError

fn clone(&self) -> BigIntError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BigIntError

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

Formats the value using the given formatter.

impl Display for BigIntError

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

Formats the value using the given formatter.

impl PartialEq for BigIntError

fn eq(&self, other: &BigIntError) -> 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 Copy for BigIntError

impl Eq for BigIntError

impl StructuralPartialEq for BigIntError