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/*

 * 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.

 *

 * $FreeBSD: src/lib/libmd/md5c.c,v 1.11 1999/12/29 05:04:20 peter Exp $

 *

 * This code is the same as the code published by RSA Inc.  It has been

 * edited for clarity and style only.

 */

#include <stdio.h>

#include <string.h>

#include "md5.hxx"

typedef unsigned int md5uint32;

static void MD5Transform(md5uint32 [4], const unsigned char [64]);

#ifdef i386

#define Encode memcpy

#define Decode memcpy

#else /* i386 */

/*

 * Encodes input (md5uint32) into output (unsigned char). Assumes len is

 * a multiple of 4.

 */

static void

Encode (unsigned char *output, md5uint32 *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 (md5uint32). Assumes len is

 * a multiple of 4.

 */

static void

Decode (md5uint32 *output, const unsigned char *input, unsigned int len)

{

  unsigned int i, j;

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

      output[i] = ((md5uint32)input[j]) | (((md5uint32)input[j+1]) << 8) |

          (((md5uint32)input[j+2]) << 16) | (((md5uint32)input[j+3]) << 24);

}

#endif /* i386 */

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) + (md5uint32)(ac); \

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

  (a) += (b); \

  }

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

  (a) += G ((b), (c), (d)) + (x) + (md5uint32)(ac); \

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

  (a) += (b); \

  }

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

  (a) += H ((b), (c), (d)) + (x) + (md5uint32)(ac); \

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

  (a) += (b); \

  }

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

  (a) += I ((b), (c), (d)) + (x) + (md5uint32)(ac); \

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

  (a) += (b); \

  }

/* 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] += ((md5uint32)inputLen << 3))

      < ((md5uint32)inputLen << 3))

      context->count[1]++;

  context->count[1] += ((md5uint32)inputLen >> 29);

  partLen = 64 - index;

  /* Transform as many times as possible. */

  if (inputLen >= partLen) {

      memcpy((void *)&context->buffer[index], (const void *)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 */

  memcpy ((void *)&context->buffer[index], (const void *)&input[i],

      inputLen-i);

}

/*

 * MD5 padding. Adds padding followed by original length.

 */

void

MD5Pad (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);

}

/*

 * 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)

{

  /* Do padding. */

  MD5Pad (context);

  /* Store state in digest */

  Encode (digest, context->state, 16);

  /* Zeroize sensitive information. */

  memset ((void *)context, 0, sizeof (*context));

}

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

static void

MD5Transform (md5uint32 state[4], const unsigned char block[64])

{

  md5uint32 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

  Decode (x, block, 64);

  /* Round 1 */

#define S11 7

#define S12 12

#define S13 17

#define S14 22

  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 */

#define S21 5

#define S22 9

#define S23 14

#define S24 20

  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 */

#define S31 4

#define S32 11

#define S33 16

#define S34 23

  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 */

#define S41 6

#define S42 10

#define S43 15

#define S44 21

  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. */

  memset ((void *)x, 0, sizeof (x));

}

/*************** Convenience  / utilities */

void MD5Final(string &digest, MD5_CTX *context)

{

    unsigned char d[16];

    MD5Final (d, context);

    digest.assign((const char *)d, 16);

}

string& MD5String(const string& data, string& digest)

{

    MD5_CTX ctx;

    MD5Init(&ctx);

    MD5Update(&ctx, (const unsigned char*)data.c_str(), data.length());

    MD5Final(digest, &ctx);

    return digest;

}

string& MD5HexPrint(const string& digest, string &out)

{

    out.erase();

    out.reserve(33);

    static const char hex[]="0123456789abcdef";

    const unsigned char *hash = (const unsigned char *)digest.c_str();

    for (int i = 0; i < 16; i++) {

  out.append(1, hex[hash[i] >> 4]);

  out.append(1, hex[hash[i] & 0x0f]);

    }

    return out;

}

string& MD5HexScan(const string& xdigest, string& digest)

{

    digest.erase();

    if (xdigest.length() != 32) {

  return digest;

    }

    for (unsigned int i = 0; i < 16; i++) {

  unsigned int val;

  if (sscanf(xdigest.c_str() + 2*i, "%2x", &val) != 1) {

      digest.erase();

      return digest;

  }

  digest.append(1, (unsigned char)val);

    }

    return digest;

}