/* 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.
 */

#include "stdafx.h"
#include "md5.h"

/* Constants for MD5Transform routine.
 */

static void MD5Transform (UINT4 [4], const unsigned char [64]);
static void Encode (unsigned char *, const UINT4 *, unsigned int);
static void Decode (UINT4 *, const unsigned char *, unsigned int);
static void MD5_memcpy (POINTER, const POINTER, unsigned int);
static void MD5_memset (POINTER, int, unsigned int);

const 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
};

#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
	
/* MD5 initialization. Begins an MD5 operation, writing a new 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.
 */
void MD5Update (MD5_CTX *context, const unsigned 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, &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.
 */
void MD5Final (unsigned 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, PADDING, padLen);

  /* Append length (before padding) */
  MD5Update (context, bits, 8);

  /* Store state in digest */
  Encode (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);

  MD5STEP(F1, a, b, c, d, x[ 0]+0xd76aa478,  7);
  MD5STEP(F1, d, a, b, c, x[ 1]+0xe8c7b756, 12);
  MD5STEP(F1, c, d, a, b, x[ 2]+0x242070db, 17);
  MD5STEP(F1, b, c, d, a, x[ 3]+0xc1bdceee, 22);
  MD5STEP(F1, a, b, c, d, x[ 4]+0xf57c0faf,  7);
  MD5STEP(F1, d, a, b, c, x[ 5]+0x4787c62a, 12);
  MD5STEP(F1, c, d, a, b, x[ 6]+0xa8304613, 17);
  MD5STEP(F1, b, c, d, a, x[ 7]+0xfd469501, 22);
  MD5STEP(F1, a, b, c, d, x[ 8]+0x698098d8,  7);
  MD5STEP(F1, d, a, b, c, x[ 9]+0x8b44f7af, 12);
  MD5STEP(F1, c, d, a, b, x[10]+0xffff5bb1, 17);
  MD5STEP(F1, b, c, d, a, x[11]+0x895cd7be, 22);
  MD5STEP(F1, a, b, c, d, x[12]+0x6b901122,  7);
  MD5STEP(F1, d, a, b, c, x[13]+0xfd987193, 12);
  MD5STEP(F1, c, d, a, b, x[14]+0xa679438e, 17);
  MD5STEP(F1, b, c, d, a, x[15]+0x49b40821, 22);
  
  MD5STEP(F2, a, b, c, d, x[ 1]+0xf61e2562,  5);
  MD5STEP(F2, d, a, b, c, x[ 6]+0xc040b340,  9);
  MD5STEP(F2, c, d, a, b, x[11]+0x265e5a51, 14);
  MD5STEP(F2, b, c, d, a, x[ 0]+0xe9b6c7aa, 20);
  MD5STEP(F2, a, b, c, d, x[ 5]+0xd62f105d,  5);
  MD5STEP(F2, d, a, b, c, x[10]+0x02441453,  9);
  MD5STEP(F2, c, d, a, b, x[15]+0xd8a1e681, 14);
  MD5STEP(F2, b, c, d, a, x[ 4]+0xe7d3fbc8, 20);
  MD5STEP(F2, a, b, c, d, x[ 9]+0x21e1cde6,  5);
  MD5STEP(F2, d, a, b, c, x[14]+0xc33707d6,  9);
  MD5STEP(F2, c, d, a, b, x[ 3]+0xf4d50d87, 14);
  MD5STEP(F2, b, c, d, a, x[ 8]+0x455a14ed, 20);
  MD5STEP(F2, a, b, c, d, x[13]+0xa9e3e905,  5);
  MD5STEP(F2, d, a, b, c, x[ 2]+0xfcefa3f8,  9);
  MD5STEP(F2, c, d, a, b, x[ 7]+0x676f02d9, 14);
  MD5STEP(F2, b, c, d, a, x[12]+0x8d2a4c8a, 20);
  
  MD5STEP(F3, a, b, c, d, x[ 5]+0xfffa3942,  4);
  MD5STEP(F3, d, a, b, c, x[ 8]+0x8771f681, 11);
  MD5STEP(F3, c, d, a, b, x[11]+0x6d9d6122, 16);
  MD5STEP(F3, b, c, d, a, x[14]+0xfde5380c, 23);
  MD5STEP(F3, a, b, c, d, x[ 1]+0xa4beea44,  4);
  MD5STEP(F3, d, a, b, c, x[ 4]+0x4bdecfa9, 11);
  MD5STEP(F3, c, d, a, b, x[ 7]+0xf6bb4b60, 16);
  MD5STEP(F3, b, c, d, a, x[10]+0xbebfbc70, 23);
  MD5STEP(F3, a, b, c, d, x[13]+0x289b7ec6,  4);
  MD5STEP(F3, d, a, b, c, x[ 0]+0xeaa127fa, 11);
  MD5STEP(F3, c, d, a, b, x[ 3]+0xd4ef3085, 16);
  MD5STEP(F3, b, c, d, a, x[ 6]+0x04881d05, 23);
  MD5STEP(F3, a, b, c, d, x[ 9]+0xd9d4d039,  4);
  MD5STEP(F3, d, a, b, c, x[12]+0xe6db99e5, 11);
  MD5STEP(F3, c, d, a, b, x[15]+0x1fa27cf8, 16);
  MD5STEP(F3, b, c, d, a, x[ 2]+0xc4ac5665, 23);
  
  MD5STEP(F4, a, b, c, d, x[ 0]+0xf4292244,  6);
  MD5STEP(F4, d, a, b, c, x[ 7]+0x432aff97, 10);
  MD5STEP(F4, c, d, a, b, x[14]+0xab9423a7, 15);
  MD5STEP(F4, b, c, d, a, x[ 5]+0xfc93a039, 21);
  MD5STEP(F4, a, b, c, d, x[12]+0x655b59c3,  6);
  MD5STEP(F4, d, a, b, c, x[ 3]+0x8f0ccc92, 10);
  MD5STEP(F4, c, d, a, b, x[10]+0xffeff47d, 15);
  MD5STEP(F4, b, c, d, a, x[ 1]+0x85845dd1, 21);
  MD5STEP(F4, a, b, c, d, x[ 8]+0x6fa87e4f,  6);
  MD5STEP(F4, d, a, b, c, x[15]+0xfe2ce6e0, 10);
  MD5STEP(F4, c, d, a, b, x[ 6]+0xa3014314, 15);
  MD5STEP(F4, b, c, d, a, x[13]+0x4e0811a1, 21);
  MD5STEP(F4, a, b, c, d, x[ 4]+0xf7537e82,  6);
  MD5STEP(F4, d, a, b, c, x[11]+0xbd3af235, 10);
  MD5STEP(F4, c, d, a, b, x[ 2]+0x2ad7d2bb, 15);
  MD5STEP(F4, b, c, d, a, x[ 9]+0xeb86d391, 21);

  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, const 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, const POINTER input, unsigned int len)
{
  unsigned int i;

  for (i = 0; i < len; i++)
	 output[i] = input[i];
}

/* Note: Replace "for loop" with standard memset if possible.
 */
static void MD5_memset (POINTER output, int value, unsigned int len)
{
  unsigned int i;

  for (i = 0; i < len; i++)
 	((char *)output)[i] = (char)value;
}

void MD5(unsigned char *out,unsigned char *in,int len)
{
	MD5_CTX ctx;

	MD5Init(&ctx);
	MD5Update(&ctx,in,len);
	MD5Final(out,&ctx);
}