Struct Source 

pub struct Source { /* private fields */ }

Deterministic pseudorandom number generator based on ChaCha8.

Wraps ChaCha8Rng to provide reproducible random sampling for lattice-based cryptographic operations. Given the same 32-byte seed, the output sequence is identical across platforms.

Not suitable for cryptographic key generation. This type is intended for deterministic test vectors, noise sampling, and reproducible benchmarks, not for generating secrets.

Implementations

impl Source

pub fn new(seed: [u8; 32]) -> Source

Creates a new Source from a 32-byte seed.

The same seed always produces the same pseudorandom sequence.

pub fn branch(&mut self) -> ([u8; 32], Source)

Derives an independent child Source for sub-stream splitting.

Draws a fresh 32-byte seed from self and returns both the seed and a new Source seeded with it. The parent and child streams are statistically independent.

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

Draws 32 random bytes suitable for use as a derived seed.

pub fn next_u64n(&mut self, max: u64, mask: u64) -> u64

Returns a uniformly distributed u64 in [0, max) using rejection sampling with bitmask mask.

mask should be max.next_power_of_two() - 1 (or wider). Each iteration draws one u64 and masks it; values >= max are rejected. Expected iterations: at most 2 when mask is tight.

pub fn next_f64(&mut self, min: f64, max: f64) -> f64

Returns a uniformly distributed f64 in [min, max).

Panics

Panics if min > max.

pub fn next_i32(&mut self) -> i32

Returns a uniformly distributed i32 (bit-reinterpretation of a random u32).

pub fn next_i64(&mut self) -> i64

Returns a uniformly distributed i64 (bit-reinterpretation of a random u64).

pub fn next_i128(&mut self) -> i128

Returns a uniformly distributed i128 (bit-reinterpretation of a random u128).

pub fn next_u128(&mut self) -> u128

Returns a uniformly distributed u128 by concatenating two u64 draws.

Trait Implementations

impl TryRng for Source

Implements TryRng by delegating to the inner ChaCha8Rng. The blanket impl<R: TryRng<Error = Infallible>> Rng for R in rand_core then provides Rng automatically.

type Error = Infallible

The type returned in the event of a RNG error.

fn try_next_u32(&mut self) -> Result<u32, <Source as TryRng>::Error>

Return the next random u32.

fn try_next_u64(&mut self) -> Result<u64, <Source as TryRng>::Error>

Return the next random u64.

fn try_fill_bytes( &mut self, bytes: &mut [u8], ) -> Result<(), <Source as TryRng>::Error>

Fill dst entirely with random data.