md4.cpp

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/*
 * libxcks
 * Copyright (C) 2022 Julien Couot
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
//---------------------------------------------------------------------------
#include <cstring>
 
#include "md4.hpp"
//---------------------------------------------------------------------------
 
using namespace std;
//---------------------------------------------------------------------------
 
 
namespace libxcks
{
// For doxygen
//---------------------------------------------------------------------------
 
 
/*
 * Default constructor.
 */
MD4::MD4()
{
  reset();
}
//---------------------------------------------------------------------------
 
 
/*
 * Resets the MD4 hash to initial value.
 */
void MD4::reset()
{
  A = 0x67452301;
  B = 0xefcdab89;
  C = 0x98badcfe;
  D = 0x10325476;
  nblocks = 0;
  count = 0;
}
//---------------------------------------------------------------------------
 
 
/*
 * Process the remaining bytes in the internal buffer and the usual
 * prolog according to the standard.
 */
void MD4::finish()
{
  uint32_t t, msb, lsb;
  uint8_t *p;
 
  update(nullptr, 0);  // flush
 
  t = nblocks;
  // multiply by 64 to make a byte count
  lsb = t << 6;
  msb = t >> 26;
  // add the count
  t = lsb;
  if ((lsb += count) < t)
    msb++;
  // multiply by 8 to make a bit count
  t = lsb;
  lsb <<= 3;
  msb <<= 3;
  msb |= t >> 29;
 
  if (count < 56)  // enough room
  {
    ibuffer[count++] = 0x80;  // pad
    while (count < 56)
      ibuffer[count++] = 0;  // pad
  }
  else  // need one extra block
  {
    ibuffer[count++] = 0x80;  // pad character
    while (count < 64)
      ibuffer[count++] = 0;
    update(nullptr, 0);  // flush
    memset(ibuffer, 0, 56 );  // fill next block with zeroes
  }
  // append the 64 bit count
  ibuffer[56] = lsb    ;
  ibuffer[57] = lsb >>  8;
  ibuffer[58] = lsb >> 16;
  ibuffer[59] = lsb >> 24;
  ibuffer[60] = msb    ;
  ibuffer[61] = msb >>  8;
  ibuffer[62] = msb >> 16;
  ibuffer[63] = msb >> 24;
  transform(ibuffer);
  //_gcry_burn_stack (80+6*sizeof(void*));
 
  p = ibuffer;
  #if (LIBXCKS_BYTE_ORDER == LIBXCKS_BIG_ENDIAN)
  #define X(a) do { *p++ = a      ; *p++ = a >> 8;      \
          *p++ = a >> 16; *p++ = a >> 24; } while(0)
  #else // little endian
  #define X(a) do { *(uint32_t*)p = a ; p += 4; } while(0)
  #endif
  X(A);
  X(B);
  X(C);
  X(D);
  #undef X
}
//---------------------------------------------------------------------------
 
 
/*
 * Updates the MD4 hash with specified array of bytes.
 */
void MD4::update(const uint8_t* buf, size_t len)
{
  if (count == 64)  // flush the buffer
  {
    transform(ibuffer);
    // _gcry_burn_stack (80+6*sizeof(void*));
    count = 0;
    nblocks++;
  }
  if (buf == nullptr)
    return;
 
  if (count != 0)
  {
    for (; len && count < 64; len--)
      ibuffer[count++] = *buf++;
    update(nullptr, 0);
    if (len == 0)
      return;
  }
  // _gcry_burn_stack (80+6*sizeof(void*));
 
  while (len >= 64)
  {
    uint8_t tmpBuf[sizeof(uint32_t) * 16];
    memcpy(tmpBuf, buf, sizeof(uint32_t) * 16);
    transform(tmpBuf);
    count = 0;
    nblocks++;
    len -= 64;
    buf += 64;
  }
  for(; len && count < 64; len--)
    ibuffer[count++] = *buf++;
}
//---------------------------------------------------------------------------
 
 
/*
 * Transform the message X which consists of 16 32-bit-words.
 */
void MD4::transform(uint8_t* data)
{
  // Helper functions
  #define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
  #define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
  #define H(x, y, z) ((x) ^ (y) ^ (z))
 
  uint32_t in[16];
  uint32_t A = this->A;
  uint32_t B = this->B;
  uint32_t C = this->C;
  uint32_t D = this->D;
 
  #if (LIBXCKS_BYTE_ORDER == LIBXCKS_BIG_ENDIAN)
  {
    int i;
    uint8_t *p2, *p1;
    for(i = 0, p1 = data, p2 = (uint8_t*)in; i < 16; i++, p2 += 4)
    {
      p2[3] = *p1++;
      p2[2] = *p1++;
      p2[1] = *p1++;
      p2[0] = *p1++;
    }
  }
  #else
  memcpy(in, data, 64);
  #endif
 
  // Round 1.
  #define function(a,b,c,d,k,s) a=rol(a+F(b,c,d)+in[k],s);
  function(A,B,C,D, 0, 3);
  function(D,A,B,C, 1, 7);
  function(C,D,A,B, 2,11);
  function(B,C,D,A, 3,19);
  function(A,B,C,D, 4, 3);
  function(D,A,B,C, 5, 7);
  function(C,D,A,B, 6,11);
  function(B,C,D,A, 7,19);
  function(A,B,C,D, 8, 3);
  function(D,A,B,C, 9, 7);
  function(C,D,A,B,10,11);
  function(B,C,D,A,11,19);
  function(A,B,C,D,12, 3);
  function(D,A,B,C,13, 7);
  function(C,D,A,B,14,11);
  function(B,C,D,A,15,19);
 
  #undef function
 
  // Round 2.
  #define function(a,b,c,d,k,s) a=rol(a+G(b,c,d)+in[k]+0x5a827999,s);
 
  function(A,B,C,D, 0, 3);
  function(D,A,B,C, 4, 5);
  function(C,D,A,B, 8, 9);
  function(B,C,D,A,12,13);
  function(A,B,C,D, 1, 3);
  function(D,A,B,C, 5, 5);
  function(C,D,A,B, 9, 9);
  function(B,C,D,A,13,13);
  function(A,B,C,D, 2, 3);
  function(D,A,B,C, 6, 5);
  function(C,D,A,B,10, 9);
  function(B,C,D,A,14,13);
  function(A,B,C,D, 3, 3);
  function(D,A,B,C, 7, 5);
  function(C,D,A,B,11, 9);
  function(B,C,D,A,15,13);
 
  #undef function
 
  // Round 3.
  #define function(a,b,c,d,k,s) a=rol(a+H(b,c,d)+in[k]+0x6ed9eba1,s);
 
  function(A,B,C,D, 0, 3);
  function(D,A,B,C, 8, 9);
  function(C,D,A,B, 4,11);
  function(B,C,D,A,12,15);
  function(A,B,C,D, 2, 3);
  function(D,A,B,C,10, 9);
  function(C,D,A,B, 6,11);
  function(B,C,D,A,14,15);
  function(A,B,C,D, 1, 3);
  function(D,A,B,C, 9, 9);
  function(C,D,A,B, 5,11);
  function(B,C,D,A,13,15);
  function(A,B,C,D, 3, 3);
  function(D,A,B,C,11, 9);
  function(C,D,A,B, 7,11);
  function(B,C,D,A,15,15);
 
 
  // Put checksum in context given as argument.
  this->A += A;
  this->B += B;
  this->C += C;
  this->D += D;
}
//---------------------------------------------------------------------------
 
 
/*
 * Returns the MD4 hash value in the first 16 bytes of the given address.
 */
uint8_t* MD4::getValue(uint8_t* buffer) const
{
  MD4 md4(*this);
  md4.finish();
 
  memcpy(buffer, md4.ibuffer, getSize());
 
  return buffer;
}
//---------------------------------------------------------------------------
}  // namespace libxcks
//---------------------------------------------------------------------------