Struct rand::chacha::ChaChaRng [−] [src]

pub struct ChaChaRng {
    buffer: [u32; STATE_WORDS],
    state: [u32; STATE_WORDS],
    index: usize,
}

Unstable (rand)
: use rand from crates.io

A random number generator that uses the ChaCha20 algorithm [1].

The ChaCha algorithm is widely accepted as suitable for cryptographic purposes, but this implementation has not been verified as such. Prefer a generator like OsRng that defers to the operating system for cases that need high security.

[1]: D. J. Bernstein, ChaCha, a variant of Salsa20

Fields

`buffer`	Unstable (`rand`) : use `rand` from crates.io
`state`	Unstable (`rand`) : use `rand` from crates.io
`index`	Unstable (`rand`) : use `rand` from crates.io

Methods

`impl ChaChaRng`

`fn new_unseeded() -> ChaChaRng`

Unstable (rand)
: use rand from crates.io

Create an ChaCha random number generator using the default fixed key of 8 zero words.

`fn set_counter(&mut self, counter_low: u64, counter_high: u64)`

Unstable (rand)
: use rand from crates.io

Sets the internal 128-bit ChaCha counter to a user-provided value. This permits jumping arbitrarily ahead (or backwards) in the pseudorandom stream.

Since the nonce words are used to extend the counter to 128 bits, users wishing to obtain the conventional ChaCha pseudorandom stream associated with a particular nonce can call this function with arguments 0, desired_nonce.

`fn init(&mut self, key: &[u32; KEY_WORDS])`

Unstable (rand)
: use rand from crates.io

Initializes self.state with the appropriate key and constants

We deviate slightly from the ChaCha specification regarding the nonce, which is used to extend the counter to 128 bits. This is provably as strong as the original cipher, though, since any distinguishing attack on our variant also works against ChaCha with a chosen-nonce. See the XSalsa20 [1] security proof for a more involved example of this.

The modified word layout is: text constant constant constant constant key key key key key key key key counter counter counter counter [1]: Daniel J. Bernstein. Extending the Salsa20 nonce.

`fn update(&mut self)`

Unstable (rand)
: use rand from crates.io

Refill the internal output buffer (self.buffer)

Struct rand::chacha::ChaChaRng [−] [src]

Fields

Methods

`impl ChaChaRng`

`fn new_unseeded() -> ChaChaRng`

`fn set_counter(&mut self, counter_low: u64, counter_high: u64)`

`fn init(&mut self, key: &[u32; KEY_WORDS])`

`fn update(&mut self)`

Trait Implementations

`impl Rng for ChaChaRng`

`fn next_u32(&mut self) -> u32`

`fn next_u64(&mut self) -> u64`

`fn next_f32(&mut self) -> f32`

`fn next_f64(&mut self) -> f64`

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

`fn gen<T: Rand>(&mut self) -> T`

`fn gen_iter<'a, T: Rand>(&'a mut self) -> Generator<'a, T, Self>`

`fn gen_range<T: PartialOrd + SampleRange>(&mut self, low: T, high: T) -> T`

`fn gen_weighted_bool(&mut self, n: usize) -> bool`

`fn gen_ascii_chars<'a>(&'a mut self) -> AsciiGenerator<'a, Self>`

`fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T>`

`fn shuffle<T>(&mut self, values: &mut [T])`

`impl<'a> SeedableRng<&'a [u32]> for ChaChaRng`

`fn reseed(&mut self, seed: &'a [u32])`

`fn from_seed(seed: &'a [u32]) -> ChaChaRng`

`impl Rand for ChaChaRng`

`fn rand<R: Rng>(other: &mut R) -> ChaChaRng`

Derived Implementations

`impl Clone for ChaChaRng`

`fn clone(&self) -> ChaChaRng`

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

`impl Copy for ChaChaRng`