BlowFishCipher Class Reference

Cryptographic blowfish cipher. More...

#include <blowfishcipher.h>

Inheritance diagram for BlowFishCipher:

[legend]Collaboration diagram for BlowFishCipher:

[legend]List of all members.

Public Member Functions
	BlowFishCipher ()
	Construct a blowfish cipher; key must be set separately.
	~BlowFishCipher ()
	Destructor: Cleans up the key data.
const Parameters *	GetPar () const
	Return pointer to static parameters.
int	SetKey (char *userkey, size_t len)
	Set the key for the following encryption/decryption.
int	CheckWeakKey ()
	Check for weak blowfish key.
int	CopyFrom (BlockCipherBase *from)
	Copy the prepared keys from another BlowFishCipher.
void	EncryptBlock (char *ibuf, char *obuf)
void	DecryptBlock (char *ibuf, char *obuf)
Static Public Attributes
const BlockCipherBase::Parameters	par
	Parameters of the block cipher.
Private Member Functions
void	_EncryptRounds (uint32 *_yl, uint32 *_yr)
void	_reset ()
	Clean up the key data.
	BlowFishCipher (const BlowFishCipher &)
	Do not use these:.
void	operator= (const BlowFishCipher &)
Private Attributes
uint32	c_P [18]
uint32	c_S [1024]

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Detailed Description

Cryptographic blowfish cipher.

Author:

Wolfgang Wieser ] wwieser (a) gmx <*> de [

Blowfish is a quite fast cipher algorithm.

ADVANTAGE: FAST

• On P100/gcc-2.95.2 -O2: 706 kb/sec encrypt+decrypt (See little file encryption program in blowfishcipher.cc; used in benchmark mode.)
• Blowfish has the reputation of being very fast but note that it is not even twice as fast as twofish implemented in twofishcipher.cc.

DISADVANTAGE: quite LARGE

• slightly more than 4kb tables as object code
• 4168b per BlowFishCipher
• about 8kb stripped i386 object code for the tables and en/decryption routines (compare to <4kb for IDEA)

Note:

sizeof(BlowFishCipher)=4168 bytes (!) snd thus nothing for small stacks..

Definition at line 55 of file blowfishcipher.h.

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Constructor & Destructor Documentation

BlowFishCipher::BlowFishCipher (  const BlowFishCipher &   )  [private]

Do not use these:.

BlowFishCipher::BlowFishCipher (   )  [inline]

Construct a blowfish cipher; key must be set separately. Definition at line 79 of file blowfishcipher.h.

BlowFishCipher::~BlowFishCipher (   )  [inline]

Destructor: Cleans up the key data. Definition at line 81 of file blowfishcipher.h. References _reset().

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Member Function Documentation

void BlowFishCipher::_EncryptRounds (  uint32 *  _yl, uint32 *  _yr )  [inline, private]

For internal use only. Do the encryption. Definition at line 309 of file blowfishcipher.cc. References c_P, c_S, ROUND, and uint32. Referenced by SetKey().

void BlowFishCipher::_reset (   )  [private]

Clean up the key data. Definition at line 489 of file blowfishcipher.cc. References c_P, c_S, and uint32. Referenced by ~BlowFishCipher().

int BlowFishCipher::CheckWeakKey (   )  [virtual]

Check for weak blowfish key. Weak blowfish keys are generated with a probability of 1:2^14 (1:16384). Returns: This returns 1, if the currently set key is weak. Returns 0 if the key is not weak. Reimplemented from BlockCipherBase. Definition at line 387 of file blowfishcipher.cc. References c_S, and uint32.

int BlowFishCipher::CopyFrom (  BlockCipherBase *  from  )  [virtual]

Copy the prepared keys from another BlowFishCipher. Returns: 0 -> OK -2 -> from is not a BlowFishCipher. Reimplemented from BlockCipherBase. Definition at line 499 of file blowfishcipher.cc. References c_P, c_S, BlockCipherBase::Parameters::cipher_ID, BlockCipherBase::GetPar(), par, and uint32.

void BlowFishCipher::DecryptBlock (  char *  ibuf, char *  obuf )  [virtual]

Reimplemented from BlockCipherBase. Definition at line 457 of file blowfishcipher.cc. References c_P, c_S, INPACK, OUTPACK, ROUND, and uint32. Referenced by test_blowfish().

void BlowFishCipher::EncryptBlock (  char *  ibuf, char *  obuf )  [virtual]

ibuf and obuf do not have to be aligned. You may set ibuf=obuf. Reimplemented from BlockCipherBase. Definition at line 424 of file blowfishcipher.cc. References c_P, c_S, INPACK, OUTPACK, ROUND, and uint32. Referenced by test_blowfish().

const Parameters* BlowFishCipher::GetPar (   )  const [inline, virtual]

Return pointer to static parameters. Reimplemented from BlockCipherBase. Definition at line 84 of file blowfishcipher.h. References par.

void BlowFishCipher::operator= (  const BlowFishCipher &   )  [private]

int BlowFishCipher::SetKey (  char *  userkey, size_t  len )  [virtual]

Set the key for the following encryption/decryption. userkey must be 128 or 256 bits long (see BlockCipher::KeyLength()). The key does not have to be aligned. The key length is passed in len (must be 16 or 32 [bytes]). Make sure, len is a value as returned by BlockCipher::KeyLength() or the functin fails. Returns: 0 -> OK; -2 -> illegal key size. Reimplemented from BlockCipherBase. Definition at line 335 of file blowfishcipher.cc. References _EncryptRounds(), bf_pbox, bf_sbox, c_P, c_S, and uint32. Referenced by test_blowfish().

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Member Data Documentation

uint32 BlowFishCipher::c_P[18] [private]

Structure for an expanded blowfish key. Definition at line 64 of file blowfishcipher.h. Referenced by _EncryptRounds(), _reset(), CopyFrom(), DecryptBlock(), EncryptBlock(), and SetKey().

uint32 BlowFishCipher::c_S[1024] [private]

Definition at line 65 of file blowfishcipher.h. Referenced by _EncryptRounds(), _reset(), CheckWeakKey(), CopyFrom(), DecryptBlock(), EncryptBlock(), and SetKey().

const BlockCipherBase::Parameters BlowFishCipher::par [static]

Initial value: { INIT_FIELD(block_size) 8, INIT_FIELD(n_key_lengths) 7, INIT_FIELD(key_length) blowfish_par_kl, INIT_FIELD(cipher_ID) 0xBF15, INIT_FIELD(name) "blowfish" } Parameters of the block cipher. Reimplemented from BlockCipherBase. Definition at line 513 of file blowfishcipher.cc. Referenced by CopyFrom(), and GetPar().

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

• /ray/src/lib/crypto/blowfishcipher.h
• /ray/src/lib/crypto/blowfishcipher.cc

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