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ARC4 Class Reference

#include <arc4.h>

Inheritance diagram for ARC4:

SymmetricCipherFinal< ARC4_Base > AlgorithmImpl< SimpleKeyingInterfaceImpl< ARC4_Base, ARC4_Base >, ARC4_Base > SimpleKeyingInterfaceImpl< ARC4_Base, ARC4_Base > ARC4_Base VariableKeyLength< 16, 1, 256 > RandomNumberGenerator SymmetricCipher SymmetricCipherDocumentation Algorithm StreamTransformation SimpleKeyingInterface Clonable Algorithm Clonable List of all members.

Detailed Description

Alleged RC4

Definition at line 35 of file arc4.h.

Public Types

typedef SymmetricCipherFinal<
ARC4_Base > 		Encryption
 implements the SymmetricCipher interface

typedef SymmetricCipherFinal<
ARC4_Base > 		Decryption
 implements the SymmetricCipher interface

enum  IV_Requirement {
  STRUCTURED_IV = 0, RANDOM_IV, UNPREDICTABLE_RANDOM_IV, INTERNALLY_GENERATED_IV,
  NOT_RESYNCHRONIZABLE
}

Public Member Functions

void SetKey (const byte *key, unsigned int length, const NameValuePairs &params=g_nullNameValuePairs)
 set or reset the key of this object

Clonable * Clone () const
 this is not implemented by most classes yet

std::string AlgorithmName () const
 returns name of this algorithm, not universally implemented yet

unsigned int MinKeyLength () const
 returns smallest valid key length in bytes */

unsigned int MaxKeyLength () const
 returns largest valid key length in bytes */

unsigned int DefaultKeyLength () const
 returns default (recommended) key length in bytes */

unsigned int GetValidKeyLength (unsigned int n) const
 returns the smallest valid key length in bytes that is >= min(n, GetMaxKeyLength())

ARC4_Base::IV_Requirement IVRequirement () const
 returns the minimal requirement for secure IVs

byte GenerateByte ()
 generate new random byte and return it

void DiscardBytes (unsigned int n)
 generate and discard n bytes

void ProcessData (byte *outString, const byte *inString, unsigned int length)
 encrypt or decrypt an array of bytes of specified length

bool IsRandomAccess () const
 returns whether this cipher supports random access

bool IsSelfInverting () const
 returns whether this transformation is self-inverting (e.g. xor with a keystream)

bool IsForwardTransformation () const
 returns whether this is an encryption object

virtual unsigned int GenerateBit ()
 generate new random bit and return it

virtual word32 GenerateWord32 (word32 a=0, word32 b=0xffffffffL)
 generate a random 32 bit word in the range min to max, inclusive

virtual void GenerateBlock (byte *output, unsigned int size)
 generate random array of bytes

template<class IT> void Shuffle (IT begin, IT end)
 randomly shuffle the specified array, resulting permutation is uniformly distributed

StreamTransformation & Ref ()
 return a reference to this object,

virtual unsigned int MandatoryBlockSize () const
 returns block size, if input must be processed in blocks, otherwise 1

virtual unsigned int OptimalBlockSize () const
 returns the input block size that is most efficient for this cipher

virtual unsigned int GetOptimalBlockSizeUsed () const
 returns how much of the current block is used up

virtual unsigned int OptimalDataAlignment () const
 returns how input should be aligned for optimal performance

virtual void ProcessLastBlock (byte *outString, const byte *inString, unsigned int length)
 for ciphers where the last block of data is special, encrypt or decrypt the last block of data

virtual unsigned int MinLastBlockSize () const
 returns the minimum size of the last block, 0 indicating the last block is not special

void ProcessString (byte *inoutString, unsigned int length)
 same as ProcessData(inoutString, inoutString, length)

void ProcessString (byte *outString, const byte *inString, unsigned int length)
 same as ProcessData(outString, inString, length)

byte ProcessByte (byte input)
 implemented as {ProcessData(&input, &input, 1); return input;}

virtual void Seek (lword n)
 for random access ciphers, seek to an absolute position

virtual bool IsValidKeyLength (unsigned int n) const
 returns whether n is a valid key length

void SetKeyWithRounds (const byte *key, unsigned int length, int rounds)
 calls SetKey() with an NameValuePairs object that just specifies "Rounds"

void SetKeyWithIV (const byte *key, unsigned int length, const byte *iv)
 calls SetKey() with an NameValuePairs object that just specifies "IV"

bool IsResynchronizable () const
 returns whether this object can be resynchronized (i.e. supports initialization vectors)

bool CanUseRandomIVs () const
 returns whether this object can use random IVs (in addition to ones returned by GetNextIV)

bool CanUsePredictableIVs () const
 returns whether this object can use random but possibly predictable IVs (in addition to ones returned by GetNextIV)

bool CanUseStructuredIVs () const
 returns whether this object can use structured IVs, for example a counter (in addition to ones returned by GetNextIV)

virtual unsigned int IVSize () const
 returns size of IVs used by this object

virtual void Resynchronize (const byte *IV)
 resynchronize with an IV

virtual void GetNextIV (byte *IV)
 get a secure IV for the next message


Static Public Member Functions

std::string StaticAlgorithmName ()
unsigned int StaticGetValidKeyLength (unsigned int n)

Protected Member Functions

void AssertValidKeyLength (unsigned int length)
void AssertValidKeyLength (unsigned int length) const
void UncheckedSetKey (const NameValuePairs &params, const byte *key, unsigned int length, const byte *iv)
virtual unsigned int GetDefaultDiscardBytes () const
void ThrowIfInvalidKeyLength (const Algorithm &algorithm, unsigned int length)
void ThrowIfResynchronizable ()
void ThrowIfInvalidIV (const byte *iv)
const byte * GetIVAndThrowIfInvalid (const NameValuePairs &params)

Protected Attributes

FixedSizeSecBlock< byte, 256 > m_state
byte m_x
byte m_y

Member Function Documentation

void SymmetricCipherFinal< ARC4_Base , ARC4_Base >::SetKey (  const byte *  key,
unsigned int  length,
const NameValuePairs &  params = g_nullNameValuePairs
)  [inline, virtual, inherited]
 

Implements SimpleKeyingInterface.

Definition at line 277 of file strciphr.h.

void ARC4_Base::DiscardBytes (  unsigned int  n  )  [virtual, inherited]
 

generate and discard n bytes

Default implementation is to call GenerateByte() n times.

Reimplemented from RandomNumberGenerator.

Definition at line 97 of file arc4.cpp.

References ARC4_Base::DiscardBytes().

Referenced by ARC4_Base::DiscardBytes().

void ARC4_Base::ProcessData (  byte *  outString,
const byte *  inString,
unsigned int  length
)  [virtual, inherited]
 

encrypt or decrypt an array of bytes of specified length

Note:
either inString == outString, or they don't overlap

Implements StreamTransformation.

Definition at line 68 of file arc4.cpp.

References ARC4_Base::ProcessData().

Referenced by ARC4_Base::ProcessData().

unsigned int RandomNumberGenerator::GenerateBit (   )  [virtual, inherited]
 

generate new random bit and return it

Default implementation is to call GenerateByte() and return its parity.

Reimplemented in PublicBlumBlumShub.

Definition at line 111 of file cryptlib.cpp.

References RandomNumberGenerator::GenerateByte().

void RandomNumberGenerator::GenerateBlock (  byte *  output,
unsigned int  size
)  [virtual, inherited]
 

generate random array of bytes

Default implementation is to call GenerateByte() size times.

Reimplemented in NonblockingRng, BlockingRng, and RandomPool.

Definition at line 116 of file cryptlib.cpp.

References RandomNumberGenerator::GenerateBlock(), and RandomNumberGenerator::GenerateByte().

Referenced by RandomNumberGenerator::GenerateBlock(), and DL_GroupParameters_DSA::GenerateRandom().

StreamTransformation& StreamTransformation::Ref (   )  [inline, inherited]
 

return a reference to this object,

This function is useful for passing a temporary StreamTransformation object to a function that takes a non-const reference.

Definition at line 464 of file cryptlib.h.

virtual unsigned int StreamTransformation::OptimalBlockSize (   )  const [inline, virtual, inherited]
 

returns the input block size that is most efficient for this cipher

Note:
optimal input length is n * OptimalBlockSize() - GetOptimalBlockSizeUsed() for any n > 0

Definition at line 471 of file cryptlib.h.

void StreamTransformation::ProcessLastBlock (  byte *  outString,
const byte *  inString,
unsigned int  length
)  [virtual, inherited]
 

for ciphers where the last block of data is special, encrypt or decrypt the last block of data

For now the only use of this function is for CBC-CTS mode.

Definition at line 101 of file cryptlib.cpp.

References StreamTransformation::MandatoryBlockSize(), StreamTransformation::MinLastBlockSize(), StreamTransformation::ProcessData(), and StreamTransformation::ProcessLastBlock().

Referenced by StreamTransformation::ProcessLastBlock().

bool SimpleKeyingInterface::IsResynchronizable (   )  const [inline, inherited]
 

returns whether this object can be resynchronized (i.e. supports initialization vectors)

If this function returns true, and no IV is passed to SetKey() and CanUseStructuredIVs()==true, an IV of all 0's will be assumed.

Definition at line 384 of file cryptlib.h.

virtual void SimpleKeyingInterface::GetNextIV (  byte *  IV  )  [inline, virtual, inherited]
 

get a secure IV for the next message

This method should be called after you finish encrypting one message and are ready to start the next one. After calling it, you must call SetKey() or Resynchronize() before using this object again. This method is not implemented on decryption objects.

Definition at line 400 of file cryptlib.h.

The documentation for this class was generated from the following file:
Generated on Sun Nov 7 08:24:00 2004 for Crypto++ by doxygen 1.3.7