Esempio n. 1
0
//Decrypt Buffer in Place
void cpl::crypt::blowfish::decrypt(buffer &buf, int iMode)
{
  int n = buf.size();

  // n MUST be a power of 8.  If not, then we are going to get very strange results.
  int rem = 8-(n%8);
  if (rem != 8)
  {
    buf.insert(buf.end(), rem, '\0');

    n += rem;
  }

  assert( n % 8 == 0 ) ;

	if (n == 0)
		return;   // Nothing to do...

	block work;
  buffer bytes(8);
  block crypt, chain(m_oChain);
  switch (iMode)
  {
  case CBC: //CBC mode, using the Chain
		for(; n >= 8; n -= 8)
		{
      copy(buf.begin()+n-8, buf.begin()+n, bytes.begin());

      work = bytesToBlock(bytes);
			crypt = work;
			decrypt(work);
			work ^= chain;
			chain = crypt;

      bytes = blockToBytes(work);

      copy(bytes.begin(), bytes.end(), buf.begin()+n-8);
		}
    break;

  case CFB: //CFB mode, using the Chain, not using Decrypt()
		for(; n >= 8; n -= 8)
		{
      copy(buf.begin()+n-8, buf.begin()+n, bytes.begin());

      work = bytesToBlock(bytes);
			encrypt(chain);
			crypt = work;
			work ^= chain;
			chain = crypt;

      bytes = blockToBytes(work);

      copy(bytes.begin(), bytes.end(), buf.begin()+n-8);
		}
    break;

  case ECB: //ECB mode, not using the Chain
  default:
		for(; n >= 8; n -= 8)
		{
      copy(buf.begin()+n-8, buf.begin()+n, bytes.begin());

      work = bytesToBlock(bytes);
			decrypt(work);
      bytes = blockToBytes(work);

      copy(bytes.begin(), bytes.end(), buf.begin()+n-8);
		}
    break;
	}

  // get the size out of the first 8 chars in the buffer, and then resize it.
  buffer sizeBuf(8);
  copy(buf.begin(), buf.begin()+8, sizeBuf.begin());
  buf.erase(buf.begin(), buf.begin()+8);

  int size = decodeInt(sizeBuf);
  
  // remove the padding from the end of the file
  buf.erase(buf.end() - (buf.size() - size), buf.end());
}
Esempio n. 2
0
//Encrypt Buffer in Place
void cpl::crypt::blowfish::encrypt(buffer &buf, int iMode)
{
	int n = buf.size();

  // encode & prepend the buffer size
  buffer sizeBuf = encodeInt(n);
  buf.insert(buf.begin(), sizeBuf.begin(), sizeBuf.end());
  n+=8;
  
  // make sure the size of the whole buffer is a factor of 8 by padding it with '\0' characters
  int rem = 8-(n%8);
  if (rem != 8)
  {
    buf.insert(buf.end(), rem, '\0');

    n += rem;
  }

	if (n == 0)
		return;   // Nothing to do...

	block work;
  buffer bytes(8);
  block chain(m_oChain);

  switch (iMode)
  {
  case CBC: //CBC mode, using the Chain
		for(; n >= 8; n -= 8)
		{
      copy(buf.begin()+n-8, buf.begin()+n, bytes.begin());

      work = bytesToBlock(bytes);
			work ^= chain;
			encrypt(work);
			chain = work;

      bytes = blockToBytes(work);

      copy(bytes.begin(), bytes.end(), buf.begin()+n-8);
    }
    break;

  case CFB: //CFB mode, using the Chain
		for(; n >= 8; n -= 8)
		{
			encrypt(chain);
      copy(buf.begin()+n-8, buf.begin()+n, bytes.begin());

      work = bytesToBlock(bytes);

      work ^= chain;
			chain = work;

      bytes = blockToBytes(work);

      copy(bytes.begin(), bytes.end(), buf.begin()+n-8);
		}
    break;

  case ECB: //ECB mode, not using the Chain
  default:
		for(; n >= 8; n -= 8)
		{
      std::copy(buf.begin()+n-8, buf.begin()+n, bytes.begin());

      work = bytesToBlock(bytes);
			encrypt(work);
      bytes = blockToBytes(work);

      copy(bytes.begin(), bytes.end(), buf.begin()+n-8);
		}
    break;
	}
}