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# PublicBlumBlumShub Class Reference

`#include <blumshub.h>`

Inheritance diagram for PublicBlumBlumShub:

List of all members.

## Detailed Description

BlumBlumShub without factorization of the modulus.

Definition at line 12 of file blumshub.h.

## Public Member Functions
| PublicBlumBlumShub (const Integer &n, const Integer &seed)
unsigned int | GenerateBit ()
| generate new random bit and return it
byte | GenerateByte ()
| generate new random byte and return it
void | ProcessData (byte *outString, const byte *inString, size_t length)
| encrypt or decrypt an array of bytes of specified length
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 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, size_t size)
| generate random array of bytes
virtual void | DiscardBytes (size_t n)
| generate and discard n bytes
template<class IT>
void | Shuffle (IT begin, IT end)
| randomly shuffle the specified array, resulting permutation is uniformly distributed
virtual std::string | AlgorithmName () const
| returns name of this algorithm, not universally implemented yet
virtual Clonable * | Clone () const
| this is not implemented by most classes yet
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, size_t 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, size_t length)
| same as ProcessData(inoutString, inoutString, length)
void | ProcessString (byte *outString, const byte *inString, size_t length)
| same as ProcessData(outString, inString, length)
byte | ProcessByte (byte input)
| implemented as {ProcessData(&input, &input, 1); return input;}
virtual bool | IsRandomAccess () const=0
| returns whether this cipher supports random access
virtual void | Seek (lword n)
| for random access ciphers, seek to an absolute position
## Protected Attributes
ModularArithmetic | modn
word | maxBits
word | bitsLeft
Integer | current
## Friends
class | BlumGoldwasserPublicKey
class | BlumGoldwasserPrivateKey

## Member Function Documentation

unsigned int PublicBlumBlumShub::GenerateBit | ( |  | ) | `[virtual]`

generate new random bit and return it

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

Reimplemented from RandomNumberGenerator.

Definition at line 16 of file blumshub.cpp.

References bitsLeft, current, Integer::GetBit(), maxBits, modn, and ModularArithmetic::Square().

Referenced by GenerateByte().

void PublicBlumBlumShub::ProcessData | ( | byte * | outString,
|  | const byte * | inString,
|  | size_t | length |
| ) |  |  | `[inline, virtual]`

encrypt or decrypt an array of bytes of specified length

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

Implements StreamTransformation.

Definition at line 21 of file blumshub.h.

void RandomNumberGenerator::GenerateBlock | ( | byte * | output,
|  | size_t | 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::GenerateByte().

Referenced by PSSR_MEM_Base::ComputeMessageRepresentative(), DL_GroupParameters_DSA::GenerateRandom(), OAEP_Base::Pad(), Integer::Randomize(), PolynomialMod2::Randomize(), and ElGamalBase::SymmetricEncrypt().

void RandomNumberGenerator::DiscardBytes | ( | size_t | n | ) | `[virtual, inherited]`

generate and discard n bytes

Default implementation is to call GenerateByte() n times.

Reimplemented in ARC4_Base.

Definition at line 142 of file cryptlib.cpp.

References RandomNumberGenerator::GenerateByte().

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

Reimplemented in ECB_OneWay.

Definition at line 471 of file cryptlib.h.

Referenced by StreamTransformationFilter::FirstPut().

void StreamTransformation::ProcessLastBlock | ( | byte * | outString,
|  | const byte * | inString,
|  | size_t | 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.

Reimplemented in CBC_CTS_Encryption, and CBC_CTS_Decryption.

Definition at line 101 of file cryptlib.cpp.

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

Referenced by StreamTransformationFilter::LastPut().

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

- blumshub.h
- blumshub.cpp