/*
 *	lib/crypto/md4/md4.c
 */

/*
 **********************************************************************
 ** md4.c                                                            **
 ** RSA Data Security, Inc. MD4 Message Digest Algorithm             **
 ** Created: 2/17/90 RLR                                             **
 ** Revised: 1/91 SRD,AJ,BSK,JT Reference C Version                  **
 **********************************************************************
 */

/*
 **********************************************************************
 ** Copyright (C) 1990, RSA Data Security, Inc. All rights reserved. **
 **                                                                  **
 ** License to copy and use this software is granted provided that   **
 ** it is identified as the "RSA Data Security, Inc. MD4 Message     **
 ** Digest Algorithm" in all material mentioning or referencing this **
 ** software or this function.                                       **
 **                                                                  **
 ** License is also granted to make and use derivative works         **
 ** provided that such works are identified as "derived from the RSA **
 ** Data Security, Inc. MD4 Message Digest Algorithm" in all         **
 ** material mentioning or referencing the derived work.             **
 **                                                                  **
 ** 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 "k5-int.h"
#include "rsa-md4.h"

/* forward declaration */
static void Transform (krb5_ui_4 *, krb5_ui_4 *);

static const unsigned char PADDING[64] = {
  0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

/* F, G and H are basic MD4 functions: selection, majority, parity */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))

/* ROTATE_LEFT rotates x left n bits */
#define ROTATE_LEFT(x, n) ((((x) << (n)) & 0xffffffff) | ((x) >> (32-(n))))

/* FF, GG and HH are MD4 transformations for rounds 1, 2 and 3 */
/* Rotation is separate from addition to prevent recomputation */
#define FF(a, b, c, d, x, s) \
  {(a) += F ((b), (c), (d)) + (x); \
   (a) &= 0xffffffff; \
   (a) = ROTATE_LEFT ((a), (s));}
#define GG(a, b, c, d, x, s) \
  {(a) += G ((b), (c), (d)) + (x) + 013240474631UL; \
   (a) &= 0xffffffff; \
   (a) = ROTATE_LEFT ((a), (s));}
#define HH(a, b, c, d, x, s) \
  {(a) += H ((b), (c), (d)) + (x) + 015666365641UL; \
   (a) &= 0xffffffff; \
   (a) = ROTATE_LEFT ((a), (s));}

void
krb5_MD4Init (krb5_MD4_CTX *mdContext)
{
  mdContext->i[0] = mdContext->i[1] = (krb5_ui_4)0;

  /* Load magic initialization constants.
   */
  mdContext->buf[0] = 0x67452301UL;
  mdContext->buf[1] = 0xefcdab89UL;
  mdContext->buf[2] = 0x98badcfeUL;
  mdContext->buf[3] = 0x10325476UL;
}

void
krb5_MD4Update (krb5_MD4_CTX *mdContext, const unsigned char *inBuf, unsigned int inLen)
{
  krb5_ui_4 in[16];
  int mdi;
  unsigned int i, ii;

  /* compute number of bytes mod 64 */
  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

  /* update number of bits */
  if ((mdContext->i[0] + ((krb5_ui_4)inLen << 3)) < mdContext->i[0])
    mdContext->i[1]++;
  mdContext->i[0] += ((krb5_ui_4)inLen << 3);
  mdContext->i[1] += ((krb5_ui_4)inLen >> 29);

  while (inLen--) {
    /* add new character to buffer, increment mdi */
    mdContext->in[mdi++] = *inBuf++;

    /* transform if necessary */
    if (mdi == 0x40) {
      for (i = 0, ii = 0; i < 16; i++, ii += 4)
        in[i] = (((krb5_ui_4)mdContext->in[ii+3]) << 24) |
                (((krb5_ui_4)mdContext->in[ii+2]) << 16) |
                (((krb5_ui_4)mdContext->in[ii+1]) << 8) |
                ((krb5_ui_4)mdContext->in[ii]);
      Transform (mdContext->buf, in);
      mdi = 0;
    }
  }
}

void
krb5_MD4Final (krb5_MD4_CTX *mdContext)
{
  krb5_ui_4 in[16];
  int mdi;
  unsigned int i, ii;
  unsigned int padLen;

  /* save number of bits */
  in[14] = mdContext->i[0];
  in[15] = mdContext->i[1];

  /* compute number of bytes mod 64 */
  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

  /* pad out to 56 mod 64 */
  padLen = (mdi < 56) ? (56 - mdi) : (120 - mdi);
  krb5_MD4Update (mdContext, PADDING, padLen);

  /* append length in bits and transform */
  for (i = 0, ii = 0; i < 14; i++, ii += 4)
    in[i] = (((krb5_ui_4)mdContext->in[ii+3]) << 24) |
            (((krb5_ui_4)mdContext->in[ii+2]) << 16) |
            (((krb5_ui_4)mdContext->in[ii+1]) << 8) |
            ((krb5_ui_4)mdContext->in[ii]);
  Transform (mdContext->buf, in);


  /* store buffer in digest */
  for (i = 0, ii = 0; i < 4; i++, ii += 4) {
    mdContext->digest[ii] = (unsigned char)(mdContext->buf[i] & 0xFF);
    mdContext->digest[ii+1] =
      (unsigned char)((mdContext->buf[i] >> 8) & 0xFF);
    mdContext->digest[ii+2] =
      (unsigned char)((mdContext->buf[i] >> 16) & 0xFF);
    mdContext->digest[ii+3] =
      (unsigned char)((mdContext->buf[i] >> 24) & 0xFF);
  }
}

/* Basic MD4 step. Transform buf based on in.
 */
static void Transform (krb5_ui_4 *buf, krb5_ui_4 *in)
{
  register krb5_ui_4 a = buf[0], b = buf[1], c = buf[2], d = buf[3];

  /* Round 1 */
  FF (a, b, c, d, in[ 0],  3);
  FF (d, a, b, c, in[ 1],  7);
  FF (c, d, a, b, in[ 2], 11);
  FF (b, c, d, a, in[ 3], 19);
  FF (a, b, c, d, in[ 4],  3);
  FF (d, a, b, c, in[ 5],  7);
  FF (c, d, a, b, in[ 6], 11);
  FF (b, c, d, a, in[ 7], 19);
  FF (a, b, c, d, in[ 8],  3);
  FF (d, a, b, c, in[ 9],  7);
  FF (c, d, a, b, in[10], 11);
  FF (b, c, d, a, in[11], 19);
  FF (a, b, c, d, in[12],  3);
  FF (d, a, b, c, in[13],  7);
  FF (c, d, a, b, in[14], 11);
  FF (b, c, d, a, in[15], 19);

  /* Round 2 */
  GG (a, b, c, d, in[ 0],  3);
  GG (d, a, b, c, in[ 4],  5);
  GG (c, d, a, b, in[ 8],  9);
  GG (b, c, d, a, in[12], 13);
  GG (a, b, c, d, in[ 1],  3);
  GG (d, a, b, c, in[ 5],  5);
  GG (c, d, a, b, in[ 9],  9);
  GG (b, c, d, a, in[13], 13);
  GG (a, b, c, d, in[ 2],  3);
  GG (d, a, b, c, in[ 6],  5);
  GG (c, d, a, b, in[10],  9);
  GG (b, c, d, a, in[14], 13);
  GG (a, b, c, d, in[ 3],  3);
  GG (d, a, b, c, in[ 7],  5);
  GG (c, d, a, b, in[11],  9);
  GG (b, c, d, a, in[15], 13);

  /* Round 3 */
  HH (a, b, c, d, in[ 0],  3);
  HH (d, a, b, c, in[ 8],  9);
  HH (c, d, a, b, in[ 4], 11);
  HH (b, c, d, a, in[12], 15);
  HH (a, b, c, d, in[ 2],  3);
  HH (d, a, b, c, in[10],  9);
  HH (c, d, a, b, in[ 6], 11);
  HH (b, c, d, a, in[14], 15);
  HH (a, b, c, d, in[ 1],  3);
  HH (d, a, b, c, in[ 9],  9);
  HH (c, d, a, b, in[ 5], 11);
  HH (b, c, d, a, in[13], 15);
  HH (a, b, c, d, in[ 3],  3);
  HH (d, a, b, c, in[11],  9);
  HH (c, d, a, b, in[ 7], 11);
  HH (b, c, d, a, in[15], 15);

  buf[0] += a;
  buf[1] += b;
  buf[2] += c;
  buf[3] += d;
}

/*
 **********************************************************************
 ** End of md4.c                                                     **
 ******************************* (cut) ********************************
 */
