pub struct RdSeed(_);
Expand description
A cryptographically secure non-deterministic random bit generator.
This generator produces high-entropy output and is suited to seed other pseudo-random generators.
This instruction currently is only available in Intel Broadwell (and later) and AMD Ryzen processors.
This generator is not intended for general random number generation purposes and should be used to seed other generators implementing rand_core::SeedableRng.
Implementations§
source§impl RdSeed
impl RdSeed
sourcepub fn new() -> Result<Self, Error>
pub fn new() -> Result<Self, Error>
Create a new instance of the random number generator.
This constructor checks whether the CPU the program is running on supports the instruction necessary for this generator to operate. If the instruction is not supported, an error is returned.
sourcepub fn try_next_u16(&self) -> Option<u16>
pub fn try_next_u16(&self) -> Option<u16>
Generate a single random u16
value.
The underlying instruction may fail for variety reasons (such as actual hardware failure or exhausted entropy), however the exact reason for the failure is not usually exposed.
This method will retry calling the instruction a few times, however if all the
attempts fail, it will return None
.
In case None
is returned, the caller should assume that an non-recoverable
hardware failure has occured and use another random number genrator instead.
sourcepub fn try_next_u32(&self) -> Option<u32>
pub fn try_next_u32(&self) -> Option<u32>
Generate a single random u32
value.
The underlying instruction may fail for variety reasons (such as actual hardware failure or exhausted entropy), however the exact reason for the failure is not usually exposed.
This method will retry calling the instruction a few times, however if all the
attempts fail, it will return None
.
In case None
is returned, the caller should assume that an non-recoverable
hardware failure has occured and use another random number genrator instead.
sourcepub fn try_next_u64(&self) -> Option<u64>
pub fn try_next_u64(&self) -> Option<u64>
Generate a single random u64
value.
The underlying instruction may fail for variety reasons (such as actual hardware failure or exhausted entropy), however the exact reason for the failure is not usually exposed.
This method will retry calling the instruction a few times, however if all the
attempts fail, it will return None
.
In case None
is returned, the caller should assume that an non-recoverable
hardware failure has occured and use another random number genrator instead.
Note, that on 32-bit targets, there’s no underlying instruction to generate a 64-bit number, so it is emulated with the 32-bit version of the instruction.
Trait Implementations§
source§impl RngCore for RdSeed
impl RngCore for RdSeed
source§fn next_u32(&mut self) -> u32
fn next_u32(&mut self) -> u32
Generate a single random u32
value.
The underlying instruction may fail for variety reasons (such as actual hardware failure or exhausted entropy), however the exact reason for the failure is not usually exposed.
Panic
This method will retry calling the instruction a few times, however if all the
attempts fail, it will panic
.
In case panic
occurs, the caller should assume that an non-recoverable
hardware failure has occured and use another random number genrator instead.
source§fn next_u64(&mut self) -> u64
fn next_u64(&mut self) -> u64
Generate a single random u64
value.
The underlying instruction may fail for variety reasons (such as actual hardware failure or exhausted entropy), however the exact reason for the failure is not usually exposed.
Note, that on 32-bit targets, there’s no underlying instruction to generate a 64-bit number, so it is emulated with the 32-bit version of the instruction.
Panic
This method will retry calling the instruction a few times, however if all the
attempts fail, it will panic
.
In case panic
occurs, the caller should assume that an non-recoverable
hardware failure has occured and use another random number genrator instead.
source§fn fill_bytes(&mut self, dest: &mut [u8])
fn fill_bytes(&mut self, dest: &mut [u8])
Fill a buffer dest
with random data.
See try_fill_bytes
for a more extensive documentation.
Panic
This method will panic any time try_fill_bytes
would return an error.
source§fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>
fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error>
Fill a buffer dest
with random data.
This method will use the most appropriate variant of the instruction available on
the machine to achieve the greatest single-core throughput, however it has a
slightly higher setup cost than the plain next_u32
or next_u64
methods.
The underlying instruction may fail for variety reasons (such as actual hardware failure or exhausted entropy), however the exact reason for the failure is not usually exposed.
This method will retry calling the instruction a few times, however if all the attempts fail, it will return an error.
If an error is returned, the caller should assume that an non-recoverable hardware failure has occured and use another random number genrator instead.