Struct rand::rngs::EntropyRng
source · [−]pub struct EntropyRng { /* private fields */ }Expand description
An interface returning random data from external source(s), provided specifically for securely seeding algorithmic generators (PRNGs).
Where possible, EntropyRng retrieves random data from the operating
system’s interface for random numbers (OsRng); if that fails it will
fall back to the JitterRng entropy collector. In the latter case it will
still try to use OsRng on the next usage.
If no secure source of entropy is available EntropyRng will panic on use;
i.e. it should never output predictable data.
This is either a little slow (OsRng requires a system call) or extremely
slow (JitterRng must use significant CPU time to generate sufficient
jitter); for better performance it is common to seed a local PRNG from
external entropy then primarily use the local PRNG (thread_rng is
provided as a convenient, local, automatically-seeded CSPRNG).
Panics
On most systems, like Windows, Linux, macOS and *BSD on common hardware, it
is highly unlikely for both OsRng and JitterRng to fail. But on
combinations like webassembly without Emscripten or stdweb both sources are
unavailable. If both sources fail, only try_fill_bytes is able to
report the error, and only the one from OsRng. The other RngCore
methods will panic in case of an error.
Implementations
sourceimpl EntropyRng
impl EntropyRng
Trait Implementations
sourceimpl Debug for EntropyRng
impl Debug for EntropyRng
sourceimpl Default for EntropyRng
impl Default for EntropyRng
sourceimpl RngCore for EntropyRng
impl RngCore for EntropyRng
impl CryptoRng for EntropyRng
Auto Trait Implementations
impl RefUnwindSafe for EntropyRng
impl Send for EntropyRng
impl Sync for EntropyRng
impl Unpin for EntropyRng
impl UnwindSafe for EntropyRng
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<R> Rng for R where
R: RngCore + ?Sized,
impl<R> Rng for R where
R: RngCore + ?Sized,
sourcefn gen<T>(&mut self) -> T where
Standard: Distribution<T>,
fn gen<T>(&mut self) -> T where
Standard: Distribution<T>,
sourcefn gen_range<T: SampleUniform, B1, B2>(&mut self, low: B1, high: B2) -> T where
B1: SampleBorrow<T> + Sized,
B2: SampleBorrow<T> + Sized,
fn gen_range<T: SampleUniform, B1, B2>(&mut self, low: B1, high: B2) -> T where
B1: SampleBorrow<T> + Sized,
B2: SampleBorrow<T> + Sized,
Generate a random value in the range [low, high), i.e. inclusive of
low and exclusive of high. Read more
sourcefn sample<T, D: Distribution<T>>(&mut self, distr: D) -> T
fn sample<T, D: Distribution<T>>(&mut self, distr: D) -> T
Sample a new value, using the given distribution. Read more
sourcefn sample_iter<'a, T, D: Distribution<T>>(
&'a mut self,
distr: &'a D
) -> DistIter<'a, D, Self, T>ⓘNotable traits for DistIter<'a, D, R, T>impl<'a, D, R, T> Iterator for DistIter<'a, D, R, T> where
D: Distribution<T>,
R: Rng + 'a, type Item = T; where
Self: Sized,
fn sample_iter<'a, T, D: Distribution<T>>(
&'a mut self,
distr: &'a D
) -> DistIter<'a, D, Self, T>ⓘNotable traits for DistIter<'a, D, R, T>impl<'a, D, R, T> Iterator for DistIter<'a, D, R, T> where
D: Distribution<T>,
R: Rng + 'a, type Item = T; where
Self: Sized,
D: Distribution<T>,
R: Rng + 'a, type Item = T;
Create an iterator that generates values using the given distribution. Read more
sourcefn fill<T: AsByteSliceMut + ?Sized>(&mut self, dest: &mut T)
fn fill<T: AsByteSliceMut + ?Sized>(&mut self, dest: &mut T)
Fill dest entirely with random bytes (uniform value distribution),
where dest is any type supporting AsByteSliceMut, namely slices
and arrays over primitive integer types (i8, i16, u32, etc.). Read more
sourcefn try_fill<T: AsByteSliceMut + ?Sized>(
&mut self,
dest: &mut T
) -> Result<(), Error>
fn try_fill<T: AsByteSliceMut + ?Sized>(
&mut self,
dest: &mut T
) -> Result<(), Error>
Fill dest entirely with random bytes (uniform value distribution),
where dest is any type supporting AsByteSliceMut, namely slices
and arrays over primitive integer types (i8, i16, u32, etc.). Read more
sourcefn gen_bool(&mut self, p: f64) -> bool
fn gen_bool(&mut self, p: f64) -> bool
Return a bool with a probability p of being true. Read more
sourcefn gen_ratio(&mut self, numerator: u32, denominator: u32) -> bool
fn gen_ratio(&mut self, numerator: u32, denominator: u32) -> bool
Return a bool with a probability of numerator/denominator of being
true. I.e. gen_ratio(2, 3) has chance of 2 in 3, or about 67%, of
returning true. If numerator == denominator, then the returned value
is guaranteed to be true. If numerator == 0, then the returned
value is guaranteed to be false. Read more
sourcefn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T>
fn choose<'a, T>(&mut self, values: &'a [T]) -> Option<&'a T>
use SliceRandom::choose instead
Return a random element from values. Read more
sourcefn choose_mut<'a, T>(&mut self, values: &'a mut [T]) -> Option<&'a mut T>
fn choose_mut<'a, T>(&mut self, values: &'a mut [T]) -> Option<&'a mut T>
use SliceRandom::choose_mut instead
Return a mutable pointer to a random element from values. Read more