/ray/src/lib/crypto/bcipherbase.cc

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/*
 * lib/crypto/bcipherbase.cc
 * 
 * Implementation of "cryptographic" null - block cipher (doing nothing). 
 * 
 * Copyright (c) 2001--2004 by Wolfgang Wieser ] wwieser (a) gmx <*> de [ 
 * 
 * This file may be distributed and/or modified under the terms of the 
 * GNU General Public License version 2 as published by the Free Software 
 * Foundation. (See COPYING.GPL for details.)
 * 
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 * 
 */

#include "bcipherbase.h"


const size_t BLOCKSIZE=8;  // we may change that 

static const size_t null_par_kl[9]={8,16,24,32,48,64,96,128,256};

const BlockCipherBase::Parameters BlockCipherBase::par = 
{
    INIT_FIELD(block_size) BLOCKSIZE,
    INIT_FIELD(n_key_lengths) 9,
    INIT_FIELD(key_length) null_par_kl,
    INIT_FIELD(cipher_ID) 0x0000,
    INIT_FIELD(name) "null"
};


int BlockCipherBase::SetKey(char * /*key*/,size_t len)
{
    for(int i=0; i<par.n_key_lengths; i++)
    {  if(par.key_length[i]==len)  return(0);  }
    return(-2);
}


// The "null" cipher never has a weak key, has it? ;)
int BlockCipherBase::CheckWeakKey()
{
    return(0);
}


void BlockCipherBase::EncryptBlock(char *ibuf,char *obuf)
{
    // Simply copy. 
    if(ibuf==obuf)  return;
    for(char *iend=ibuf+BLOCKSIZE; ibuf<iend; ibuf++,obuf++)
    {  *obuf=*ibuf;  }
}


void BlockCipherBase::DecryptBlock(char *ibuf,char *obuf)
{
    // Simply copy. 
    if(ibuf==obuf)  return;
    for(char *iend=ibuf+BLOCKSIZE; ibuf<iend; ibuf++,obuf++)
    {  *obuf=*ibuf;  }
}


int BlockCipherBase::CopyFrom(BlockCipherBase *bcb)
{
    if(!bcb || bcb->GetPar()->cipher_ID!=par.cipher_ID)  return(-2);
    // Nothing to do...
    return(0);
}

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