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Salsa20_Policy Class Reference

Salsa20 stream cipher operation. More...

#include <salsa.h>

Inheritance diagram for Salsa20_Policy:
AdditiveCipherConcretePolicy< word32, 16 > AdditiveCipherAbstractPolicy XSalsa20_Policy

Protected Member Functions

void CipherSetKey (const NameValuePairs &params, const byte *key, size_t length)
 Key the cipher.
 
void OperateKeystream (KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)
 Operates the keystream.
 
void CipherResynchronize (byte *keystreamBuffer, const byte *IV, size_t length)
 Resynchronize the cipher.
 
bool CipherIsRandomAccess () const
 Flag indicating random access.
 
void SeekToIteration (lword iterationCount)
 Seeks to a random position in the stream.
 
std::string AlgorithmProvider () const
 Retrieve the provider of this algorithm.
 
 CRYPTOPP_CONSTANT (ROUNDS=20)
 

Protected Attributes

FixedSizeAlignedSecBlock< word32, 16 > m_state
 
int m_rounds
 

Additional Inherited Members

- Public Types inherited from AdditiveCipherConcretePolicy< word32, 16 >
typedef word32 WordType
 Word type for the cipher.
 
- Public Member Functions inherited from AdditiveCipherConcretePolicy< word32, 16 >
 CRYPTOPP_CONSTANT (BYTES_PER_ITERATION=sizeof(WordType) *W)
 Number of bytes for an iteration.
 
unsigned int GetAlignment () const
 Provides data alignment requirements.
 
unsigned int GetBytesPerIteration () const
 Provides number of bytes operated upon during an iteration.
 
unsigned int GetIterationsToBuffer () const
 Provides buffer size based on iterations.
 
bool CanOperateKeystream () const
 Flag indicating.
 
- Public Member Functions inherited from AdditiveCipherAbstractPolicy
virtual unsigned int GetOptimalBlockSize () const
 Provides number of ideal bytes to process.
 
virtual void WriteKeystream (byte *keystream, size_t iterationCount)
 Generate the keystream.
 

Detailed Description

Salsa20 stream cipher operation.

Since
Crypto++ 5.4

Definition at line 38 of file salsa.h.

Constructor & Destructor Documentation

◆ Salsa20_Policy()

Salsa20_Policy::Salsa20_Policy ( )
inlineprotected

Definition at line 41 of file salsa.h.

Member Function Documentation

◆ AlgorithmProvider()

std::string Salsa20_Policy::AlgorithmProvider ( ) const
protectedvirtual

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.

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 116 of file salsa.cpp.

◆ CipherIsRandomAccess()

bool Salsa20_Policy::CipherIsRandomAccess ( ) const
inlineprotectedvirtual

Flag indicating random access.

Returns
true if the cipher is seekable, false otherwise
See also
SeekToIteration()

Implements AdditiveCipherAbstractPolicy.

Definition at line 45 of file salsa.h.

◆ CipherResynchronize()

void Salsa20_Policy::CipherResynchronize ( byte keystreamBuffer,
const byte iv,
size_t  length 
)
protectedvirtual

Resynchronize the cipher.

Parameters
keystreamBufferthe keystream buffer
iva byte array used to resynchronize the cipher
lengththe size of the IV array

Reimplemented from AdditiveCipherAbstractPolicy.

Reimplemented in XSalsa20_Policy.

Definition at line 148 of file salsa.cpp.

◆ CipherSetKey()

void Salsa20_Policy::CipherSetKey ( const NameValuePairs params,
const byte key,
size_t  length 
)
protectedvirtual

Key the cipher.

Parameters
paramsset of NameValuePairs use to initialize this object
keya byte array used to key the cipher
lengththe size of the key array

Implements AdditiveCipherAbstractPolicy.

Reimplemented in XSalsa20_Policy.

Definition at line 125 of file salsa.cpp.

◆ OperateKeystream()

void Salsa20_Policy::OperateKeystream ( KeystreamOperation  operation,
byte output,
const byte input,
size_t  iterationCount 
)
protectedvirtual

Operates the keystream.

Parameters
operationthe operation with additional flags
outputthe output buffer
inputthe input buffer
iterationCountthe number of iterations to perform on the input

OperateKeystream() will attempt to operate upon GetOptimalBlockSize() buffer, which will be derived from GetBytesPerIteration().

See also
CanOperateKeystream(), OperateKeystream(), WriteKeystream(), KeystreamOperation()

Implements AdditiveCipherConcretePolicy< word32, 16 >.

Definition at line 196 of file salsa.cpp.

◆ SeekToIteration()

void Salsa20_Policy::SeekToIteration ( lword  iterationCount)
protectedvirtual

Seeks to a random position in the stream.

See also
CipherIsRandomAccess()

Reimplemented from AdditiveCipherAbstractPolicy.

Definition at line 158 of file salsa.cpp.

Member Data Documentation

◆ m_rounds

int Salsa20_Policy::m_rounds
protected

Definition at line 57 of file salsa.h.

◆ m_state

FixedSizeAlignedSecBlock<word32, 16> Salsa20_Policy::m_state
protected

Definition at line 56 of file salsa.h.


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