Crypto++  8.2
Free C++ class library of cryptographic schemes
Public Member Functions | Static Public Member Functions | List of all members
DARN Class Reference

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

+ Inheritance diagram for DARN:

Public Member Functions

 DARN ()
 Construct a DARN 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 ClonableClone () const
 Copies this object. More...
 

Static Public Member Functions

static const char * StaticAlgorithmName ()
 

Detailed Description

Hardware generated random numbers using DARN instruction.

DARN() provides access to Power9's random number generator. The Crypto++ implementation provides conditioned random numbers from the generator as opposed to raw random numbers. According to Power ISA 3.0B manual, a conditioned random number has been processed by hardware to reduce bias. A raw random number is unconditioned noise source output.

According to Power ISA 3.0B manual, the random number generator provided by the darn instruction is NIST SP800-90B and SP800-90C compliant to the extent possible given the completeness of the standards at the time the hardware is designed. The random number generator provides a minimum of 0.5 bits of entropy per bit.

Wraps
darn instruction
See also
Power ISA Version 3.0B, MaurerRandomnessTest() for random bit generators
Since
Crypto++ 8.0

Definition at line 51 of file darn.h.

Constructor & Destructor Documentation

◆ DARN()

DARN::DARN ( )

Construct a DARN generator.

Exceptions
DARN_Errif the random number generator is not available

Definition at line 216 of file darn.cpp.

Member Function Documentation

◆ GenerateBlock()

void DARN::GenerateBlock ( byte *  output,
size_t  size 
)
virtual

Generate random array of bytes.

Parameters
outputthe byte buffer
sizethe length of the buffer, in bytes

Reimplemented from RandomNumberGenerator.

Definition at line 221 of file darn.cpp.

◆ DiscardBytes()

void DARN::DiscardBytes ( size_t  n)
virtual

Generate and discard n bytes.

Parameters
nthe 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 227 of file darn.cpp.

◆ IncorporateEntropy()

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

Update RNG state with additional unpredictable values.

Parameters
inputunused
lengthunused

The operation is a nop for this generator.

Reimplemented from RandomNumberGenerator.

Definition at line 78 of file darn.h.

◆ AlgorithmProvider()

std::string DARN::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 darn.h.


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