/*

MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm

Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All

rights reserved.

License to copy and use this software is granted provided that it

is identified as the "RSA Data Security, Inc. MD5 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. MD5 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.

 */

/*!

 * \file

 * \brief MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm

 */

#include <string.h>

#include "md5global.h"

#include "md5.h"

#define USE_MEM

/* Constants for MD5Transform routine.

 */

#define S11 7

#define S12 12

#define S13 17

#define S14 22

#define S21 5

#define S22 9

#define S23 14

#define S24 20

#define S31 4

#define S32 11

#define S33 16

#define S34 23

#define S41 6

#define S42 10

#define S43 15

#define S44 21

static void MD5Transform(UINT4 [4], const unsigned char [64]);

static void Encode(unsigned char *, UINT4 *, unsigned int);

static void Decode(UINT4 *, const unsigned char *, unsigned int);

static void MD5_memcpy(POINTER, POINTER, unsigned int);

static void MD5_memset(POINTER, int, unsigned int);

static unsigned char PADDING[64] = {

  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

};

/* F, G, H and I are basic MD5 functions.

 */

#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))

#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))

#define H(x, y, z) ((x) ^ (y) ^ (z))

#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits.

 */

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.

Rotation is separate from addition to prevent recomputation.

 */

#define FF(a, b, c, d, x, s, ac) { \

 (a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

#define GG(a, b, c, d, x, s, ac) { \

 (a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

#define HH(a, b, c, d, x, s, ac) { \

 (a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

#define II(a, b, c, d, x, s, ac) { \

 (a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \

 (a) = ROTATE_LEFT ((a), (s)); \

 (a) += (b); \

  }

/* MD5 initialization. Begins an MD5 operation, writing a new context.

   MD5_CTX *context - context

 */

void MD5Init (MD5_CTX *context)

{

  context->count[0] = context->count[1] = 0;

  /* Load magic initialization constants.

*/

  context->state[0] = 0x67452301;

  context->state[1] = 0xefcdab89;

  context->state[2] = 0x98badcfe;

  context->state[3] = 0x10325476;

}

/* MD5 block update operation. Continues an MD5 message-digest

   operation, processing another message block, and updating the

   context.

   MD5_CTX *context - context

   unsigned char *input - input block

   unsigned int inputLen - length of input block

 */

void MD5Update (MD5_CTX *context, const char *input, unsigned int inputLen)

{

  unsigned int i, index, partLen;

  /* Compute number of bytes mod 64 */

  index = (unsigned int)((context->count[0] >> 3) & 0x3F);

  /* Update number of bits */

  if ((context->count[0] += ((UINT4)inputLen << 3))

   < ((UINT4)inputLen << 3))

 context->count[1]++;

  context->count[1] += ((UINT4)inputLen >> 29);

  partLen = 64 - index;

  /* Transform as many times as possible.

*/

  if (inputLen >= partLen) {

 MD5_memcpy

   ((POINTER)&context->buffer[index], (POINTER)input, partLen);

 MD5Transform (context->state, context->buffer);

 for (i = partLen; i + 63 < inputLen; i += 64)

   MD5Transform (context->state, (const unsigned char *)(&input[i]));

 index = 0;

  }

  else

 i = 0;

  /* Buffer remaining input */

  MD5_memcpy

 ((POINTER)&context->buffer[index], (POINTER)&input[i],

  inputLen-i);

}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the

  the message digest and zeroizing the context.

  unsigned char digest[16] - message digest

  MD5_CTX *context - context

 */

void MD5Final (char digest[16], MD5_CTX *context)

{

  unsigned char bits[8];

  unsigned int index, padLen;

  /* Save number of bits */

  Encode (bits, context->count, 8);

  /* Pad out to 56 mod 64.

*/

  index = (unsigned int)((context->count[0] >> 3) & 0x3f);

  padLen = (index < 56) ? (56 - index) : (120 - index);

  MD5Update (context, (const char *)PADDING, padLen);

  /* Append length (before padding) */

  MD5Update (context, (const char *)bits, 8);

  /* Store state in digest */

  Encode ((unsigned char *)digest, context->state, 16);

  /* Zeroize sensitive information.

*/

  MD5_memset ((POINTER)context, 0, sizeof (*context));

}

/* MD5 basic transformation. Transforms state based on block.

 */

static void MD5Transform (UINT4 state[4], const unsigned char block[64])

{

  UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

  Decode (x, block, 64);

  /* Round 1 */

  FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */

  FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */

  FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */

  FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */

  FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */

  FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */

  FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */

  FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */

  FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */

  FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */

  FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */

  FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */

  FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */

  FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */

  FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */

  FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

 /* Round 2 */

  GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */

  GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */

  GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */

  GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */

  GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */

  GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */

  GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */

  GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */

  GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */

  GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */

  GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */

  GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */

  GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */

  GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */

  GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */

  GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

  /* Round 3 */

  HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */

  HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */

  HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */

  HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */

  HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */

  HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */

  HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */

  HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */

  HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */

  HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */

  HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */

  HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */

  HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */

  HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */

  HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */

  HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

  /* Round 4 */

  II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */

  II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */

  II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */

  II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */

  II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */

  II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */

  II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */

  II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */

  II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */

  II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */

  II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */

  II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */

  II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */

  II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */

  II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */

  II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

  state[0] += a;

  state[1] += b;

  state[2] += c;

  state[3] += d;

  /* Zeroize sensitive information.

*/

  MD5_memset ((POINTER)x, 0, sizeof (x));

}

/* Encodes input (UINT4) into output (unsigned char). Assumes len is

  a multiple of 4.

 */

static void Encode (unsigned char *output, UINT4 *input, unsigned int len)

{

  unsigned int i, j;

  for (i = 0, j = 0; j < len; i++, j += 4) {

 output[j] = (unsigned char)(input[i] & 0xff);

 output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);

 output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);

 output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);

  }

}

/* Decodes input (unsigned char) into output (UINT4). Assumes len is

  a multiple of 4.

 */

static void Decode (UINT4 *output, const unsigned char *input, unsigned int len)

{

  unsigned int i, j;

  for (i = 0, j = 0; j < len; i++, j += 4)

 output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |

   (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);

}

/* Note: Replace "for loop" with standard memcpy if possible.

 */

static void MD5_memcpy (POINTER output, POINTER input, unsigned int len)

{

#ifndef USE_MEM

  unsigned int i;

  for (i = 0; i < len; i++)

 output[i] = input[i];

#else

  memcpy( output, input, len );

#endif

}

/* Note: Replace "for loop" with standard memset if possible.

 */

static void MD5_memset (POINTER output, int value, unsigned int len)

{

#ifndef USE_MEM

  unsigned int i;

  for (i = 0; i < len; i++)

 ((char *)output)[i] = (char)value;

#else

  memset( output, value, len );

#endif

}