blowfish Namespace Reference

Namespaces
namespace	core
	Low-level utilities - for advanced users only.
Classes
struct	Block
	Unit of encryption. Block of data processed together during an encryption cycle. More...
struct	Pad
	Data pad used for encryption. Pseudo-random block used to have varying encryption results. More...
Typedefs
typedef core::BlockIterator	DIter
	Iterator used to traverse data in all encryption routines below.
Enumerations
enum	{ kBlockSize = 2*4 }
	Source and destination data sizes must be multiples of this value. More...
Functions
Pad	generatePad (void const *keyPtr, int keyLen)
	Returns an encription pad generated using the specified key/password.
Block	operator^ (Block const &a, Block const &b)
	Returns a new block made of the xor-ed fields of a and b.
void	encrypt_ECB (Pad const &pad, void const *src, void *dst, size_t byteSize)
void	decrypt_ECB (Pad const &pad, void const *src, void *dst, size_t byteSize)
void	encrypt_CBC (Pad const &pad, void const *src, void *dst, size_t byteSize, Block *pChain)
void	decrypt_CBC (Pad const &pad, void const *src, void *dst, size_t byteSize, Block *pChain)
void	encrypt_CFB (Pad const &pad, void const *src, void *dst, size_t byteSize, Block *pChain)
void	decrypt_CFB (Pad const &pad, void const *src, void *dst, size_t byteSize, Block *pChain)

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Typedef Documentation

typedef core::BlockIterator blowfish::DIter

Iterator used to traverse data in all encryption routines below.

Definition at line 471 of file blowfish.cpp.

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Enumeration Type Documentation

anonymous enum

Source and destination data sizes must be multiples of this value.

Enumerator:

kBlockSize

Definition at line 24 of file blowfish.h.

{ kBlockSize = 2*4 }; ///< two 4-byte words.

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Function Documentation

void blowfish::decrypt_CBC	(	Pad const &	pad,
		void const *	src,
		void *	dst,
		size_t	byteSize,
		Block *	pChain
	)

Definition at line 513 of file blowfish.cpp.

{
   Block chain(0,0);
   if( pChain ) chain = *pChain;
   DIter       srcScan(src);
   DIter const srcEnd (src, byteSize);
   DIter       dstScan(dst);
   for(  ; srcScan != srcEnd ; ++srcScan, ++dstScan )
   {
        Block crypt = *srcScan;
        *dstScan = chain ^ core::decipherBlock( pad, crypt );
        chain = crypt;
    }
   if( pChain ) *pChain = chain;
}

void blowfish::decrypt_CFB	(	Pad const &	pad,
		void const *	src,
		void *	dst,
		size_t	byteSize,
		Block *	pChain
	)

Definition at line 542 of file blowfish.cpp.

{
   Block chain(0,0);
   if( pChain ) chain = *pChain;
   DIter       srcScan(src);
   DIter const srcEnd (src, byteSize);
   DIter       dstScan(dst);
   for(  ; srcScan != srcEnd ; ++srcScan, ++dstScan )
   {
        Block crypt = *srcScan;
        *dstScan = crypt ^ core::encipherBlock( pad, chain );
        chain = crypt;
    }
   if( pChain ) *pChain = chain;
}

void blowfish::decrypt_ECB	(	Pad const &	pad,
		void const *	src,
		void *	dst,
		size_t	byteSize
	)

Definition at line 491 of file blowfish.cpp.

{
   DIter       srcScan(src);
   DIter const srcEnd (src, byteSize);
   DIter       dstScan(dst);
   for(  ; srcScan != srcEnd ; ++srcScan, ++dstScan )
        *dstScan = core::decipherBlock( pad, *srcScan );
}

void blowfish::encrypt_CBC	(	Pad const &	pad,
		void const *	src,
		void *	dst,
		size_t	byteSize,
		Block *	pChain
	)

Definition at line 501 of file blowfish.cpp.

{
   Block chain(0,0);
   if( pChain ) chain = *pChain;
   DIter       srcScan(src);
   DIter const srcEnd (src, byteSize);
   DIter       dstScan(dst);
   for(  ; srcScan != srcEnd ; ++srcScan, ++dstScan )
      *dstScan = chain = core::encipherBlock( pad, *srcScan ^ chain );
   if( pChain ) *pChain = chain;
}

void blowfish::encrypt_CFB	(	Pad const &	pad,
		void const *	src,
		void *	dst,
		size_t	byteSize,
		Block *	pChain
	)

Definition at line 530 of file blowfish.cpp.

{
   Block chain(0,0);
   if( pChain ) chain = *pChain;
   DIter       srcScan(src);
   DIter const srcEnd (src, byteSize);
   DIter       dstScan(dst);
   for(  ; srcScan != srcEnd ; ++srcScan, ++dstScan )
      *dstScan = chain = ( *srcScan ^ core::encipherBlock( pad, chain ) );
   if( pChain ) *pChain = chain;
}

void blowfish::encrypt_ECB	(	Pad const &	pad,
		void const *	src,
		void *	dst,
		size_t	byteSize
	)

Encryption Modes

• ECB : Direct encryption of independent blocks (no data chaining).
• CBC : Encrypt after xor-ing source with previous encrypted result.
• CFB : Destination is source xor-ed with encrypted previous result.

Definition at line 482 of file blowfish.cpp.

{
   DIter       srcScan(src);
   DIter const srcEnd (src, byteSize);
   DIter       dstScan(dst);
   for(  ; srcScan != srcEnd ; ++srcScan, ++dstScan )
      *dstScan = core::encipherBlock( pad, *srcScan );
}

Pad blowfish::generatePad	(	void const *const	keyPtr,
		int const	keyLen
	)

Returns an encription pad generated using the specified key/password.

Definition at line 432 of file blowfish.cpp.

{
   if( keyLen < 1  ||  keyLen > 56  )
       throw std::exception("Invalid key length used to initialize BlowFish.");

   Pad ans = core::defaultPiPad;

   // Load P boxes with key bytes, by xor-ing the entire array with key data (which is cycled through).
   unsigned char const* const keyBase = reinterpret_cast<const uint8*>(keyPtr);
   unsigned char const* const keyEnd  = keyBase + keyLen;
   unsigned char const*       keyScan = keyBase;
   uint32*       boxScan = ans.P;
   uint32* const boxEnd  = ans.P+18;
   do {
      uint32 word = 0; // need to work on a block-by-block basis, as endianness within the P buffer may vary
      for( unsigned i = 4 ; i ; --i )
      {
         word = (word<<8) | *keyScan++;
         if( keyScan == keyEnd ) keyScan = keyBase;
      }
      *boxScan++ ^= word;
   } while( boxScan != boxEnd );

   // Use blowfish to reflectively scramble P and S boxes, while evolving the Blowfish pad.
   Block block(0,0); //zeroed start block
   uint32*       scanPad = reinterpret_cast<uint32*>( &ans );
   uint32* const endPad  = reinterpret_cast<uint32*>( &ans + 1 );
   do {
      block = core::encipherBlock( ans, block );
      *scanPad++ = block.L;
      *scanPad++ = block.R;
   } while( scanPad != endPad );

   return ans;
}

Block blowfish::operator^	(	Block const &	a,
		Block const &	b
	)			[inline]

Returns a new block made of the xor-ed fields of a and b.

Definition at line 476 of file blowfish.cpp.

{ return Block( a.L ^ b.L , a.R ^ b.R ); }