Scrypt key derivation function. More...

#include <scrypt.h>

Inheritance diagram for Scrypt:

Public Member Functions
std::string	AlgorithmName () const
	Provides the name of this algorithm.

size_t	MaxDerivedKeyLength () const
	Determine maximum number of bytes.

size_t	GetValidDerivedLength (size_t keylength) const
	Returns a valid key length for the derivation function.

size_t	DeriveKey (byte derived, size_t derivedLen, const byte secret, size_t secretLen, const NameValuePairs &params) const
	Derive a key from a seed.

size_t	DeriveKey (byte derived, size_t derivedLen, const byte secret, size_t secretLen, const byte *salt, size_t saltLen, word64 cost=2, word64 blockSize=8, word64 parallelization=1) const
	Derive a key from a seed.

Public Member Functions inherited from KeyDerivationFunction
virtual size_t	MinDerivedKeyLength () const
	Determine minimum number of bytes.

virtual bool	IsValidDerivedLength (size_t keylength) const
	Returns whether keylength is a valid key length.

virtual void	SetParameters (const NameValuePairs &params)
	Set or change parameters.

Public Member Functions inherited from Algorithm
	Algorithm (bool checkSelfTestStatus=true)
	Interface for all crypto algorithms.

virtual std::string	AlgorithmProvider () const
	Retrieve the provider of this algorithm.

Public Member Functions inherited from Clonable
virtual Clonable *	Clone () const
	Copies this object.

Static Public Member Functions
static std::string	StaticAlgorithmName ()

Protected Types
enum	{ defaultCost =2 , defaultBlockSize =8 , defaultParallelization =1 }

Protected Member Functions
const Algorithm &	GetAlgorithm () const
	Returns the base class Algorithm.

void	ValidateParameters (size_t derivedlen, word64 cost, word64 blockSize, word64 parallelization) const

Protected Member Functions inherited from KeyDerivationFunction
void	ThrowIfInvalidDerivedKeyLength (size_t length) const
	Validates the derived key length.

Detailed Description

Scrypt key derivation function.

The Crypto++ implementation uses OpenMP to accelerate the derivation when available.

The Crypto++ implementation of Scrypt is limited by C++ datatypes. For example, the library is limited to a derived key length of SIZE_MAX, and not (2^32 - 1) * 32.

See also: Stronger Key Derivation via Sequential Memory-Hard Functions, The scrypt key derivation function and RFC 7914, The scrypt Password-Based Key Derivation Function

Since: Crypto++ 7.0

Definition at line 33 of file scrypt.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

protected

Definition at line 91 of file scrypt.h.

Constructor & Destructor Documentation

◆ ~Scrypt()

virtual Scrypt::~Scrypt ( )

inlinevirtual

Definition at line 36 of file scrypt.h.

Member Function Documentation

◆ AlgorithmName()

std::string Scrypt::AlgorithmName ( ) const

inlinevirtual

Provides the name of this algorithm.

Returns: the standard algorithm name

Implements KeyDerivationFunction.

Definition at line 43 of file scrypt.h.

◆ DeriveKey() [1/2]

size_t Scrypt::DeriveKey	(	byte *	derived,
		size_t	derivedLen,
		const byte *	secret,
		size_t	secretLen,
		const byte *	salt,
		size_t	saltLen,
		word64	cost = `2`,
		word64	blockSize = `8`,
		word64	parallelization = `1`
	)		const

Derive a key from a seed.

Parameters

derived	the derived output buffer
derivedLen	the size of the derived buffer, in bytes
secret	the seed input buffer
secretLen	the size of the secret buffer, in bytes
salt	the salt input buffer
saltLen	the size of the salt buffer, in bytes
cost	the CPU/memory cost factor
blockSize	the block size
parallelization	the parallelization factor

Returns: the number of iterations performed

Exceptions

InvalidDerivedKeyLength if derivedLen is invalid for the scheme

DeriveKey() provides a standard interface to derive a key from a seed and other parameters. Each class that derives from KeyDerivationFunction provides an overload that accepts most parameters used by the derivation function.

The CPU/Memory cost parameter ("N" in the documents) must be larger than 1, a power of 2, and less than 2^(128 * r / 8).

The parameter blockSize ("r" in the documents) specifies the block size.

The parallelization parameter ("p" in the documents) is a positive integer less than or equal to ((2^32-1) * 32) / (128 * r). Due to Microsoft and its OpenMP 2.0 implementation parallelization is limited to std::numeric_limits<int>::max().

Scrypt always returns 1 because it only performs 1 iteration. Other derivation functions, like PBKDF's, will return more interesting values.

The Crypto++ implementation of Scrypt is limited by C++ datatypes. For example, the library is limited to a derived key length of SIZE_MAX, and not (2^32 - 1) * 32.

Definition at line 282 of file scrypt.cpp.

◆ DeriveKey() [2/2]

size_t Scrypt::DeriveKey	(	byte *	derived,
		size_t	derivedLen,
		const byte *	secret,
		size_t	secretLen,
		const NameValuePairs &	params
	)		const

virtual

Derive a key from a seed.

Parameters

derived	the derived output buffer
derivedLen	the size of the derived buffer, in bytes
secret	the seed input buffer
secretLen	the size of the secret buffer, in bytes
params	additional initialization parameters to configure this object

Returns: the number of iterations performed

Exceptions

InvalidDerivedKeyLength if derivedLen is invalid for the scheme

DeriveKey() provides a standard interface to derive a key from a secret seed and other parameters. Each class that derives from KeyDerivationFunction provides an overload that accepts most parameters used by the derivation function.

the number of iterations performed by DeriveKey() may be 1. For example, a scheme like HKDF does not use the iteration count so it returns 1.

Implements KeyDerivationFunction.

Definition at line 259 of file scrypt.cpp.

◆ GetAlgorithm()

const Algorithm & Scrypt::GetAlgorithm ( ) const

inlineprotectedvirtual

Returns the base class Algorithm.

Returns: the base class Algorithm

Implements KeyDerivationFunction.

Definition at line 94 of file scrypt.h.

◆ GetValidDerivedLength()

ANONYMOUS_NAMESPACE_END size_t Scrypt::GetValidDerivedLength ( size_t keylength ) const

virtual

Returns a valid key length for the derivation function.

Parameters

keylength the size of the derived key, in bytes

Returns: the valid key length, in bytes

Implements KeyDerivationFunction.

Definition at line 178 of file scrypt.cpp.

◆ MaxDerivedKeyLength()

size_t Scrypt::MaxDerivedKeyLength ( ) const

inlinevirtual

Determine maximum number of bytes.

Returns: Maximum number of bytes which can be derived

Reimplemented from KeyDerivationFunction.

Definition at line 48 of file scrypt.h.

◆ StaticAlgorithmName()

static std::string Scrypt::StaticAlgorithmName ( )

inlinestatic

Definition at line 38 of file scrypt.h.

◆ ValidateParameters()

void Scrypt::ValidateParameters	(	size_t	derivedlen,
		word64	cost,
		word64	blockSize,
		word64	parallelization
	)		const

inlineprotected

Definition at line 185 of file scrypt.cpp.

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

G:/work/subversion/scol-technologies/trunk/scol/plugins/security/cryptopp/scrypt.h
G:/work/subversion/scol-technologies/trunk/scol/plugins/security/cryptopp/scrypt.cpp

Public Member Functions

Static Public Member Functions

Protected Types

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ ~Scrypt()

Member Function Documentation

◆ AlgorithmName()

◆ DeriveKey() [1/2]

◆ DeriveKey() [2/2]

◆ GetAlgorithm()

◆ GetValidDerivedLength()

◆ MaxDerivedKeyLength()

◆ StaticAlgorithmName()

◆ ValidateParameters()