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md4.c

/* 
   Unix SMB/Netbios implementation.
   Version 1.9.
   a implementation of MD4 designed for use in the SMB authentication protocol
   Copyright (C) Andrew Tridgell 1997
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 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 General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/


/* NOTE: This code makes no attempt to be fast! 

   It assumes that a int is at least 32 bits long
*/

typedef unsigned int uint32;

static uint32 A, B, C, D;

static uint32 F(uint32 X, uint32 Y, uint32 Z)
{
      return (X&Y) | ((~X)&Z);
}

static uint32 G(uint32 X, uint32 Y, uint32 Z)
{
      return (X&Y) | (X&Z) | (Y&Z); 
}

static uint32 H(uint32 X, uint32 Y, uint32 Z)
{
      return X^Y^Z;
}

static uint32 lshift(uint32 x, int s)
{
      x &= 0xFFFFFFFF;
      return ((x<<s)&0xFFFFFFFF) | (x>>(32-s));
}

#define ROUND1(a,b,c,d,k,s) a = lshift(a + F(b,c,d) + X[k], s)
#define ROUND2(a,b,c,d,k,s) a = lshift(a + G(b,c,d) + X[k] + (uint32)0x5A827999,s)
#define ROUND3(a,b,c,d,k,s) a = lshift(a + H(b,c,d) + X[k] + (uint32)0x6ED9EBA1,s)

/* this applies md4 to 64 byte chunks */
static void mdfour64(uint32 *M)
{
      int j;
      uint32 AA, BB, CC, DD;
      uint32 X[16];

      for (j=0;j<16;j++)
            X[j] = M[j];

      AA = A; BB = B; CC = C; DD = D;

        ROUND1(A,B,C,D,  0,  3);  ROUND1(D,A,B,C,  1,  7);  
      ROUND1(C,D,A,B,  2, 11);  ROUND1(B,C,D,A,  3, 19);
        ROUND1(A,B,C,D,  4,  3);  ROUND1(D,A,B,C,  5,  7);  
      ROUND1(C,D,A,B,  6, 11);  ROUND1(B,C,D,A,  7, 19);
        ROUND1(A,B,C,D,  8,  3);  ROUND1(D,A,B,C,  9,  7);  
      ROUND1(C,D,A,B, 10, 11);  ROUND1(B,C,D,A, 11, 19);
        ROUND1(A,B,C,D, 12,  3);  ROUND1(D,A,B,C, 13,  7);  
      ROUND1(C,D,A,B, 14, 11);  ROUND1(B,C,D,A, 15, 19);    

        ROUND2(A,B,C,D,  0,  3);  ROUND2(D,A,B,C,  4,  5);  
      ROUND2(C,D,A,B,  8,  9);  ROUND2(B,C,D,A, 12, 13);
        ROUND2(A,B,C,D,  1,  3);  ROUND2(D,A,B,C,  5,  5);  
      ROUND2(C,D,A,B,  9,  9);  ROUND2(B,C,D,A, 13, 13);
        ROUND2(A,B,C,D,  2,  3);  ROUND2(D,A,B,C,  6,  5);  
      ROUND2(C,D,A,B, 10,  9);  ROUND2(B,C,D,A, 14, 13);
        ROUND2(A,B,C,D,  3,  3);  ROUND2(D,A,B,C,  7,  5);  
      ROUND2(C,D,A,B, 11,  9);  ROUND2(B,C,D,A, 15, 13);

      ROUND3(A,B,C,D,  0,  3);  ROUND3(D,A,B,C,  8,  9);  
      ROUND3(C,D,A,B,  4, 11);  ROUND3(B,C,D,A, 12, 15);
        ROUND3(A,B,C,D,  2,  3);  ROUND3(D,A,B,C, 10,  9);  
      ROUND3(C,D,A,B,  6, 11);  ROUND3(B,C,D,A, 14, 15);
        ROUND3(A,B,C,D,  1,  3);  ROUND3(D,A,B,C,  9,  9);  
      ROUND3(C,D,A,B,  5, 11);  ROUND3(B,C,D,A, 13, 15);
        ROUND3(A,B,C,D,  3,  3);  ROUND3(D,A,B,C, 11,  9);  
      ROUND3(C,D,A,B,  7, 11);  ROUND3(B,C,D,A, 15, 15);

      A += AA; B += BB; C += CC; D += DD;
      
      A &= 0xFFFFFFFF; B &= 0xFFFFFFFF;
      C &= 0xFFFFFFFF; D &= 0xFFFFFFFF;

      for (j=0;j<16;j++)
            X[j] = 0;
}

static void copy64(uint32 *M, unsigned char *in)
{
      int i;

      for (i=0;i<16;i++)
            M[i] = (in[i*4+3]<<24) | (in[i*4+2]<<16) |
                  (in[i*4+1]<<8) | (in[i*4+0]<<0);
}

static void copy4(unsigned char *out,uint32 x)
{
      out[0] = x&0xFF;
      out[1] = (x>>8)&0xFF;
      out[2] = (x>>16)&0xFF;
      out[3] = (x>>24)&0xFF;
}

/* produce a md4 message digest from data of length n bytes */
void mdfour(unsigned char *out, unsigned char *in, int n)
{
      unsigned char buf[128];
      uint32 M[16];
      uint32 b = n * 8;
      int i;

      A = 0x67452301;
      B = 0xefcdab89;
      C = 0x98badcfe;
      D = 0x10325476;

      while (n > 64) {
            copy64(M, in);
            mdfour64(M);
            in += 64;
            n -= 64;
      }

      for (i=0;i<128;i++)
            buf[i] = 0;
      memcpy(buf, in, n);
      buf[n] = 0x80;
      
      if (n <= 55) {
            copy4(buf+56, b);
            copy64(M, buf);
            mdfour64(M);
      } else {
            copy4(buf+120, b); 
            copy64(M, buf);
            mdfour64(M);
            copy64(M, buf+64);
            mdfour64(M);
      }

      for (i=0;i<128;i++)
            buf[i] = 0;
      copy64(M, buf);

      copy4(out, A);
      copy4(out+4, B);
      copy4(out+8, C);
      copy4(out+12, D);

      A = B = C = D = 0;
}



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