RDRAND Class Reference

Hardware generated random numbers using RDRAND instruction. More...

#include <rdrand.h>

Inheritance diagram for RDRAND:

Public Member Functions
	RDRAND ()
	Construct a RDRAND generator.
virtual void	GenerateBlock (byte *output, size_t size)
	Generate random array of bytes.
virtual void	DiscardBytes (size_t n)
	Generate and discard n bytes.
virtual void	IncorporateEntropy (const byte *input, size_t length)
	Update RNG state with additional unpredictable values.
std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm.
Public Member Functions inherited from RandomNumberGenerator
virtual bool	CanIncorporateEntropy () const
	Determines if a generator can accept additional entropy.
virtual byte	GenerateByte ()
	Generate new random byte and return it.
virtual unsigned int	GenerateBit ()
	Generate new random bit and return it.
virtual word32	GenerateWord32 (word32 min=0, word32 max=0xffffffffUL)
	Generate a random 32 bit word in the range min to max, inclusive.
virtual void	GenerateIntoBufferedTransformation (BufferedTransformation &target, const std::string &channel, lword length)
	Generate random bytes into a BufferedTransformation.
template<class IT >
void	Shuffle (IT begin, IT end)
	Randomly shuffle the specified array.
Public Member Functions inherited from Algorithm
	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms.
virtual std::string	AlgorithmName () const
	Provides the name of this algorithm.
Public Member Functions inherited from Clonable
virtual Clonable *	Clone () const
	Copies this object.

Static Public Member Functions
static const char *	StaticAlgorithmName ()

Detailed Description

Hardware generated random numbers using RDRAND instruction.

See also

MaurerRandomnessTest() for random bit generators

Since

Crypto++ 5.6.3

Definition at line 48 of file rdrand.h.

Constructor & Destructor Documentation

~RDRAND()

virtual RDRAND::~RDRAND ( )

inlinevirtual

Definition at line 53 of file rdrand.h.

RDRAND()

RDRAND::RDRAND

(

)

Construct a RDRAND generator.

According to DJ of Intel, the Intel RDRAND circuit does not underflow. If it did hypothetically underflow, then it would return 0 for the random value. AMD's RDRAND implementation appears to provide the same behavior.

Exceptions

RDRAND_Err

if the random number generator is not available

Definition at line 287 of file rdrand.cpp.

Member Function Documentation

StaticAlgorithmName()

static const char * RDRAND::StaticAlgorithmName ( )

inlinestatic

Definition at line 51 of file rdrand.h.

GenerateBlock()

void RDRAND::GenerateBlock ( byte * output, size_t size )

virtual

Generate random array of bytes.

Parameters

output	the byte buffer
size	the length of the buffer, in bytes

Reimplemented from RandomNumberGenerator.

Definition at line 292 of file rdrand.cpp.

DiscardBytes()

void RDRAND::DiscardBytes ( size_t n )

virtual

Generate and discard n bytes.

Parameters

n	the number of bytes to generate and discard

the RDSEED generator discards words, not bytes. If n is not a multiple of a machine word, then it is rounded up to that size.

Reimplemented from RandomNumberGenerator.

Definition at line 298 of file rdrand.cpp.

IncorporateEntropy()

virtual void RDRAND::IncorporateEntropy ( const byte * input, size_t length )

inlinevirtual

Update RNG state with additional unpredictable values.

Parameters

input	unused
length	unused

The operation is a nop for this generator.

Reimplemented from RandomNumberGenerator.

Definition at line 78 of file rdrand.h.

AlgorithmProvider()

std::string RDRAND::AlgorithmProvider ( ) const

inlinevirtual

Retrieve the provider of this algorithm.

Returns

the algorithm provider

The algorithm provider can be a name like "C++", "SSE", "NEON", "AESNI", "ARMv8" and "Power8". C++ is standard C++ code. Other labels, like SSE, usually indicate a specialized implementation using instructions from a higher instruction set architecture (ISA). Future labels may include external hardware like a hardware security module (HSM).

Generally speaking Wei Dai's original IA-32 ASM code falls under "SSE2". Labels like "SSSE3" and "SSE4.1" follow after Wei's code and use intrinsics instead of ASM.

Algorithms which combine different instructions or ISAs provide the dominant one. For example on x86 AES/GCM returns "AESNI" rather than "CLMUL" or "AES+SSE4.1" or "AES+CLMUL" or "AES+SSE4.1+CLMUL".

Note

Provider is not universally implemented yet.

Since

Crypto++ 8.0

Reimplemented from Algorithm.

Definition at line 84 of file rdrand.h.

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The documentation for this class was generated from the following files:

• rdrand.h
• rdrand.cpp