Crypto++ 8.2 Free C++ class library of cryptographic schemes

Public Member Functions | Static Public Member Functions | List of all members
RDRAND Class Reference

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

Inheritance diagram for RDRAND:

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

## 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()

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

## ◆ 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
| ) |  |
| inline virtual

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
| inline virtual

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.

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

- rdrand.h
- rdrand.cpp