Type Alias ChaChaRng

pub type ChaChaRng = ChaCha20Rng;

ChaCha with 20 rounds

Aliased Type

struct ChaChaRng { /* private fields */ }

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 320 bytes

Implementations

impl ChaCha20Rng

pub fn get_word_pos(&self) -> u128

Get the offset from the start of the stream, in 32-bit words.

Since the generated blocks are 16 words (2⁴) long and the counter is 64-bits, the offset is a 68-bit number. Sub-word offsets are not supported, hence the result can simply be multiplied by 4 to get a byte-offset.

pub fn set_word_pos(&mut self, word_offset: u128)

Set the offset from the start of the stream, in 32-bit words.

As with get_word_pos, we use a 68-bit number. Since the generator simply cycles at the end of its period (1 ZiB), we ignore the upper 60 bits.

pub fn set_stream(&mut self, stream: u64)

Set the stream number.

This is initialized to zero; 2⁶⁴ unique streams of output are available per seed/key.

Note that in order to reproduce ChaCha output with a specific 64-bit nonce, one can convert that nonce to a u64 in little-endian fashion and pass to this function. In theory a 96-bit nonce can be used by passing the last 64-bits to this function and using the first 32-bits as the most significant half of the 64-bit counter (which may be set indirectly via set_word_pos), but this is not directly supported.

pub fn get_stream(&self) -> u64

Get the stream number.

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

Get the seed.

Trait Implementations

impl Clone for ChaCha20Rng

fn clone(&self) -> ChaCha20Rng

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ChaCha20Rng

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

Formats the value using the given formatter.

impl From<ChaCha20Core> for ChaCha20Rng

fn from(core: ChaCha20Core) -> Self

Converts to this type from the input type.

impl PartialEq for ChaCha20Rng

fn eq(&self, rhs: &ChaCha20Rng) -> 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 RngCore for ChaCha20Rng

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, bytes: &mut [u8])

Fill dest with random data.

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

Fill dest entirely with random data.

impl SeedableRng for ChaCha20Rng

type Seed = [u8; 32]

Seed type, which is restricted to types mutably-dereferenceable as u8 arrays (we recommend [u8; N] for some N).

fn from_seed(seed: Self::Seed) -> Self

Create a new PRNG using the given seed.

fn seed_from_u64(state: u64) -> Self

Create a new PRNG using a u64 seed.

fn from_rng<R>(rng: R) -> Result<Self, Error>

where R: RngCore,

Create a new PRNG seeded from another Rng.

fn from_entropy() -> Self

Creates a new instance of the RNG seeded via getrandom.

impl CryptoRng for ChaCha20Rng

impl Eq for ChaCha20Rng