Type Alias rand_chacha::ChaChaRng

pub type ChaChaRng = ChaCha20Rng;

ChaCha with 20 rounds

Aliased Type

struct ChaChaRng { /* private fields */ }

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<ChaCha20Rng> for ChaCha20Rng

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

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method 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