DefaultRandomSource in std::random - Rust
Description: The default random source.

## DefaultRandomSource

# Struct DefaultRandomSource

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    pub struct DefaultRandomSource;

🔬This is a nightly-only experimental API. (`random` #130703)
Expand description

The default random source.

This asks the system for random data suitable for cryptographic purposes such as key generation. If security is a concern, consult the platform documentation below for the specific guarantees your target provides.

The high quality of randomness provided by this source means it can be quite slow on some targets. If you need a large quantity of random numbers and security is not a concern, consider using an alternative random number generator (potentially seeded from this one).

## §Underlying sources

Platform | Source
--- | ---
Linux | `getrandom` or `/dev/urandom` after polling `/dev/random`
Windows | `ProcessPrng`
Apple | `CCRandomGenerateBytes`
DragonFly | `arc4random_buf`
ESP-IDF | `esp_fill_random`
FreeBSD | `arc4random_buf`
Fuchsia | `cprng_draw`
Haiku | `arc4random_buf`
Illumos | `arc4random_buf`
NetBSD | `arc4random_buf`
OpenBSD | `arc4random_buf`
Solaris | `arc4random_buf`
Vita | `arc4random_buf`
Hermit | `read_entropy`
Horizon, Cygwin | `getrandom`
AIX, Hurd, L4Re, QNX | `/dev/urandom`
Redox | `/scheme/rand`
RTEMS | `arc4random_buf`
SGX | `rdrand`
SOLID | `SOLID_RNG_SampleRandomBytes`
TEEOS | `TEE_GenerateRandom`
UEFI | `EFI_RNG_PROTOCOL`
VxWorks | `randABytes` after waiting for `randSecure` to become ready
WASI | `random_get`
ZKVM | `sys_rand`

Note that the sources used might change over time.

Consult the documentation for the underlying operations on your supported targets to determine whether they provide any particular desired properties, such as support for reseeding on VM fork operations.

## Trait Implementations§

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### impl Clone for DefaultRandomSource

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#### fn clone(&self) -> DefaultRandomSource

Returns a duplicate of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for DefaultRandomSource

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

Formats the value using the given formatter. Read more
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### impl Default for DefaultRandomSource

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#### fn default() -> DefaultRandomSource

Returns the “default value” for a type. Read more
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### impl RandomSource for DefaultRandomSource

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#### fn fill_bytes(&mut self, bytes: &mut [u8])

🔬This is a nightly-only experimental API. (`random` #130703)
Fills `bytes` with random bytes. Read more
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### impl Copy for DefaultRandomSource

## Auto Trait Implementations§

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### impl Freeze for DefaultRandomSource

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### impl RefUnwindSafe for DefaultRandomSource

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### impl Send for DefaultRandomSource

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### impl Sync for DefaultRandomSource

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### impl Unpin for DefaultRandomSource

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### impl UnwindSafe for DefaultRandomSource

## Blanket Implementations§

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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.