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MD2Engine.cpp

//
// MD2Engine.cpp
//
// $Id: //poco/1.3/Foundation/src/MD2Engine.cpp#2 $
//
// Library: Foundation
// Package: Crypt
// Module:  MD2Engine
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//
//
// MD2 (RFC 1319) algorithm:
// Copyright (C) 1990-2, RSA Data Security, Inc. Created 1990. All
// rights reserved.
//
// License to copy and use this software is granted for
// non-commercial Internet Privacy-Enhanced Mail provided that it is
// identified as the "RSA Data Security, Inc. MD2 Message Digest
// Algorithm" in all material mentioning or referencing this software
// or this function.
//
// RSA Data Security, Inc. makes no representations concerning either
// the merchantability of this software or the suitability of this
// software for any particular purpose. It is provided "as is"
// without express or implied warranty of any kind.
//
// These notices must be retained in any copies of any part of this
// documentation and/or software.
//


#include "Poco/MD2Engine.h"
#include <cstring>


namespace Poco {


MD2Engine::MD2Engine()
{
      _digest.reserve(16);
      reset();
}


MD2Engine::~MD2Engine()
{
      reset();
}

      
00076 void MD2Engine::updateImpl(const void* input_, unsigned inputLen)
{
      const unsigned char* input = (const unsigned char*) input_;
      unsigned int i, index, partLen;

      /* Update number of bytes mod 16 */
      index = _context.count;
      _context.count = (index + inputLen) & 0xf;

      partLen = 16 - index;

      /* Transform as many times as possible.   */
      if (inputLen >= partLen) 
      {
            std::memcpy(&_context.buffer[index], input, partLen);
            transform(_context.state, _context.checksum, _context.buffer);

            for (i = partLen; i + 15 < inputLen; i += 16)
                  transform(_context.state, _context.checksum, &input[i]);

            index = 0;
      }
      else i = 0;

      /* Buffer remaining input */
      std::memcpy(&_context.buffer[index], &input[i], inputLen-i);
}


00105 unsigned MD2Engine::digestLength() const
{
      return DIGEST_SIZE;
}


00111 void MD2Engine::reset()
{
      std::memset(&_context, 0, sizeof(_context));
}


00117 const DigestEngine::Digest& MD2Engine::digest()
{
      static const unsigned char* PADDING[] = 
      {
            (unsigned char*) "",
            (unsigned char*) "\001",
            (unsigned char*) "\002\002",
            (unsigned char*) "\003\003\003",
            (unsigned char*) "\004\004\004\004",
            (unsigned char*) "\005\005\005\005\005",
            (unsigned char*) "\006\006\006\006\006\006",
            (unsigned char*) "\007\007\007\007\007\007\007",
            (unsigned char*) "\010\010\010\010\010\010\010\010",
            (unsigned char*) "\011\011\011\011\011\011\011\011\011",
            (unsigned char*) "\012\012\012\012\012\012\012\012\012\012",
            (unsigned char*) "\013\013\013\013\013\013\013\013\013\013\013",
            (unsigned char*) "\014\014\014\014\014\014\014\014\014\014\014\014",
            (unsigned char*) "\015\015\015\015\015\015\015\015\015\015\015\015\015",
            (unsigned char *) "\016\016\016\016\016\016\016\016\016\016\016\016\016\016",
            (unsigned char *) "\017\017\017\017\017\017\017\017\017\017\017\017\017\017\017",
            (unsigned char *) "\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020"
      };
      unsigned int index, padLen;

      /* Pad out to multiple of 16. */
      index = _context.count;
      padLen = 16 - index;
      update((const char*) PADDING[padLen], padLen);

      /* Extend with checksum */
      update((const char*) _context.checksum, 16);

      /* Store state in digest */
      _digest.clear();
      _digest.insert(_digest.begin(), _context.state, _context.state + 16);

      /* Zeroize sensitive information. */
      std::memset(&_context, 0, sizeof(_context));
      reset();
      return _digest;
}


void MD2Engine::transform(unsigned char state[16], unsigned char checksum[16], const unsigned char block[16])
{
      // Permutation of 0..255 constructed from the digits of pi. It gives a
      // "random" nonlinear byte substitution operation.
      static const unsigned char PI_SUBST[256] = 
      {
            41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
            19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
            76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
            138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
            245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
            148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
            39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
            181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
            150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
            112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
            96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
            85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
            234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
            129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
            8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
            203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
            166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
            31, 26, 219, 153, 141, 51, 159, 17, 131, 20
      };
      unsigned int i, j, t;
      unsigned char x[48];

      /* Form encryption block from state, block, state ^ block. */
      std::memcpy(x, state, 16);
      std::memcpy(x+16, block, 16);
      for (i = 0; i < 16; i++)
            x[i+32] = state[i] ^ block[i];

      /* Encrypt block (18 rounds). */
      t = 0;
      for (i = 0; i < 18; i++) 
      {
            for (j = 0; j < 48; j++)
                  t = x[j] ^= PI_SUBST[t];
            t = (t + i) & 0xff;
      }

      /* Save new state */
      std::memcpy(state, x, 16);

      /* Update checksum. */
      t = checksum[15];
      for (i = 0; i < 16; i++)
      t = checksum[i] ^= PI_SUBST[block[i] ^ t];

      /* Zeroize sensitive information. */
      std::memset(x, 0, sizeof(x));
}


} // namespace Poco

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