Struct RpxRandomCoin

pub struct RpxRandomCoin { /* private fields */ }

A simplified version of the SPONGE_PRG reseedable pseudo-random number generator algorithm described in https://eprint.iacr.org/2011/499.pdf.

The simplification is related to the following facts:

1. A call to the reseed method implies one and only one call to the permutation function. This is possible because in our case we never reseed with more than 4 field elements.
2. As a result of the previous point, we don’t make use of an input buffer to accumulate seed material.

Implementations

impl RpxRandomCoin

pub fn new(seed: Word) -> Self

Returns a new RpxRandomCoin initialize with the specified seed.

pub fn from_parts(state: [Felt; 12], current: usize) -> Self

Returns an RpxRandomCoin instantiated from the provided components.

Panics

Panics if current is smaller than 4 or greater than or equal to 12.

pub fn into_parts(self) -> ([Felt; 12], usize)

Returns components of this random coin.

pub fn fill_bytes(&mut self, dest: &mut [u8])

Fills dest with random data.

Trait Implementations

impl Clone for RpxRandomCoin

fn clone(&self) -> RpxRandomCoin

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for RpxRandomCoin

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

Formats the value using the given formatter.

impl Deserializable for RpxRandomCoin

fn read_from<R: ByteReader>( source: &mut R, ) -> Result<Self, DeserializationError>

Reads a sequence of bytes from the provided source, attempts to deserialize these bytes into Self, and returns the result.

fn read_from_bytes(bytes: &[u8]) -> Result<Self, DeserializationError>

Attempts to deserialize the provided bytes into Self and returns the result.

impl FeltRng for RpxRandomCoin

fn draw_element(&mut self) -> Felt

Draw, uniformly at random, a base field element.

fn draw_word(&mut self) -> Word

Draw, uniformly at random, a Word.

impl PartialEq for RpxRandomCoin

fn eq(&self, other: &RpxRandomCoin) -> 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 RandomCoin for RpxRandomCoin

type BaseField = BaseElement

Base field for random elements which can be generated by this random coin.

type Hasher = Rpx256

Hash function which is used by the random coin to generate random field elements.

fn new(seed: &[Self::BaseField]) -> Self

Returns a new random coin instantiated with the provided seed.

fn reseed(&mut self, data: RpxDigest)

Reseeds the coin with the specified data by setting the new seed to hash(seed || data).

fn check_leading_zeros(&self, value: u64) -> u32

Computes hash(seed || value) and returns the number of leading zeros in the resulting value if it is interpreted as an integer in big-endian byte order.

fn draw<E: FieldElement<BaseField = Felt>>( &mut self, ) -> Result<E, RandomCoinError>

Returns the next pseudo-random field element.

fn draw_integers( &mut self, num_values: usize, domain_size: usize, nonce: u64, ) -> Result<Vec<usize>, RandomCoinError>

Returns a vector of integers selected from the range [0, domain_size) after it reseeds the coin with a nonce.

impl RngCore for RpxRandomCoin

fn next_u32(&mut self) -> u32

Return the next random u32.

fn next_u64(&mut self) -> u64

Return the next random u64.

fn fill_bytes(&mut self, dest: &mut [u8])

Fill dest with random data.

fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>

Fill dest entirely with random data.

impl Serializable for RpxRandomCoin

fn write_into<W: ByteWriter>(&self, target: &mut W)

Serializes self into bytes and writes these bytes into the target.

fn to_bytes(&self) -> Vec<u8>

Serializes self into a vector of bytes.

fn get_size_hint(&self) -> usize

Returns an estimate of how many bytes are needed to represent self.

impl Copy for RpxRandomCoin

impl Eq for RpxRandomCoin

impl StructuralPartialEq for RpxRandomCoin