/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [email protected], http://libtomcrypt.org
 */

/* MD5 hash function by Tom St Denis */

#include "mycrypt.h"

#ifdef MD5

const struct _hash_descriptor md5_desc =
{
    "md5",
    3,
    16,
    64,
    &md5_init,
    &md5_process,
    &md5_done,
    &md5_test
};

#define F(x,y,z)  (z ^ (x & (y ^ z)))
#define G(x,y,z)  (y ^ (z & (y ^ x)))
#define H(x,y,z)  (x^y^z)
#define I(x,y,z)  (y^(x|(~z)))

#define FF(a,b,c,d,M,s,t) \
    a = (a + F(b,c,d) + M + t); a = ROL(a, s) + b;

#define GG(a,b,c,d,M,s,t) \
    a = (a + G(b,c,d) + M + t); a = ROL(a, s) + b;

#define HH(a,b,c,d,M,s,t) \
    a = (a + H(b,c,d) + M + t); a = ROL(a, s) + b;

#define II(a,b,c,d,M,s,t) \
    a = (a + I(b,c,d) + M + t); a = ROL(a, s) + b;

#ifdef CLEAN_STACK
static void _md5_compress(hash_state *md, unsigned char *buf)
#else
static void md5_compress(hash_state *md, unsigned char *buf)
#endif
{
    ulong32 i, W[16], a, b, c, d;

    /* copy the state into 512-bits into W[0..15] */
    for (i = 0; i < 16; i++) {
        LOAD32L(W[i], buf + (4*i));
    }
 
    /* copy state */
    a = md->md5.state[0];
    b = md->md5.state[1];
    c = md->md5.state[2];
    d = md->md5.state[3];

    FF(a,b,c,d,W[0],7,0xd76aa478UL)
    FF(d,a,b,c,W[1],12,0xe8c7b756UL)
    FF(c,d,a,b,W[2],17,0x242070dbUL)
    FF(b,c,d,a,W[3],22,0xc1bdceeeUL)
    FF(a,b,c,d,W[4],7,0xf57c0fafUL)
    FF(d,a,b,c,W[5],12,0x4787c62aUL)
    FF(c,d,a,b,W[6],17,0xa8304613UL)
    FF(b,c,d,a,W[7],22,0xfd469501UL)
    FF(a,b,c,d,W[8],7,0x698098d8UL)
    FF(d,a,b,c,W[9],12,0x8b44f7afUL)
    FF(c,d,a,b,W[10],17,0xffff5bb1UL)
    FF(b,c,d,a,W[11],22,0x895cd7beUL)
    FF(a,b,c,d,W[12],7,0x6b901122UL)
    FF(d,a,b,c,W[13],12,0xfd987193UL)
    FF(c,d,a,b,W[14],17,0xa679438eUL)
    FF(b,c,d,a,W[15],22,0x49b40821UL)
    GG(a,b,c,d,W[1],5,0xf61e2562UL)
    GG(d,a,b,c,W[6],9,0xc040b340UL)
    GG(c,d,a,b,W[11],14,0x265e5a51UL)
    GG(b,c,d,a,W[0],20,0xe9b6c7aaUL)
    GG(a,b,c,d,W[5],5,0xd62f105dUL)
    GG(d,a,b,c,W[10],9,0x02441453UL)
    GG(c,d,a,b,W[15],14,0xd8a1e681UL)
    GG(b,c,d,a,W[4],20,0xe7d3fbc8UL)
    GG(a,b,c,d,W[9],5,0x21e1cde6UL)
    GG(d,a,b,c,W[14],9,0xc33707d6UL)
    GG(c,d,a,b,W[3],14,0xf4d50d87UL)
    GG(b,c,d,a,W[8],20,0x455a14edUL)
    GG(a,b,c,d,W[13],5,0xa9e3e905UL)
    GG(d,a,b,c,W[2],9,0xfcefa3f8UL)
    GG(c,d,a,b,W[7],14,0x676f02d9UL)
    GG(b,c,d,a,W[12],20,0x8d2a4c8aUL)
    HH(a,b,c,d,W[5],4,0xfffa3942UL)
    HH(d,a,b,c,W[8],11,0x8771f681UL)
    HH(c,d,a,b,W[11],16,0x6d9d6122UL)
    HH(b,c,d,a,W[14],23,0xfde5380cUL)
    HH(a,b,c,d,W[1],4,0xa4beea44UL)
    HH(d,a,b,c,W[4],11,0x4bdecfa9UL)
    HH(c,d,a,b,W[7],16,0xf6bb4b60UL)
    HH(b,c,d,a,W[10],23,0xbebfbc70UL)
    HH(a,b,c,d,W[13],4,0x289b7ec6UL)
    HH(d,a,b,c,W[0],11,0xeaa127faUL)
    HH(c,d,a,b,W[3],16,0xd4ef3085UL)
    HH(b,c,d,a,W[6],23,0x04881d05UL)
    HH(a,b,c,d,W[9],4,0xd9d4d039UL)
    HH(d,a,b,c,W[12],11,0xe6db99e5UL)
    HH(c,d,a,b,W[15],16,0x1fa27cf8UL)
    HH(b,c,d,a,W[2],23,0xc4ac5665UL)
    II(a,b,c,d,W[0],6,0xf4292244UL)
    II(d,a,b,c,W[7],10,0x432aff97UL)
    II(c,d,a,b,W[14],15,0xab9423a7UL)
    II(b,c,d,a,W[5],21,0xfc93a039UL)
    II(a,b,c,d,W[12],6,0x655b59c3UL)
    II(d,a,b,c,W[3],10,0x8f0ccc92UL)
    II(c,d,a,b,W[10],15,0xffeff47dUL)
    II(b,c,d,a,W[1],21,0x85845dd1UL)
    II(a,b,c,d,W[8],6,0x6fa87e4fUL)
    II(d,a,b,c,W[15],10,0xfe2ce6e0UL)
    II(c,d,a,b,W[6],15,0xa3014314UL)
    II(b,c,d,a,W[13],21,0x4e0811a1UL)
    II(a,b,c,d,W[4],6,0xf7537e82UL)
    II(d,a,b,c,W[11],10,0xbd3af235UL)
    II(c,d,a,b,W[2],15,0x2ad7d2bbUL)
    II(b,c,d,a,W[9],21,0xeb86d391UL)

    md->md5.state[0] = md->md5.state[0] + a;
    md->md5.state[1] = md->md5.state[1] + b;
    md->md5.state[2] = md->md5.state[2] + c;
    md->md5.state[3] = md->md5.state[3] + d;
}

#ifdef CLEAN_STACK
static void md5_compress(hash_state *md, unsigned char *buf)
{
   _md5_compress(md, buf);
   burn_stack(sizeof(ulong32) * 21);
}
#endif

void md5_init(hash_state * md)
{
   _ARGCHK(md != NULL);
   md->md5.state[0] = 0x67452301UL;
   md->md5.state[1] = 0xefcdab89UL;
   md->md5.state[2] = 0x98badcfeUL;
   md->md5.state[3] = 0x10325476UL;
   md->md5.curlen = 0;
   md->md5.length = 0;
}

HASH_PROCESS(md5_process, md5_compress, md5, 64)

int md5_done(hash_state * md, unsigned char *hash)
{
    int i;

    _ARGCHK(md != NULL);
    _ARGCHK(hash != NULL);

    if (md->md5.curlen >= sizeof(md->md5.buf)) {
       return CRYPT_INVALID_ARG;
    }


    /* increase the length of the message */
    md->md5.length += md->md5.curlen * 8;

    /* append the '1' bit */
    md->md5.buf[md->md5.curlen++] = (unsigned char)0x80;

    /* if the length is currently above 56 bytes we append zeros
     * then compress.  Then we can fall back to padding zeros and length
     * encoding like normal.
     */
    if (md->md5.curlen > 56) {
        while (md->md5.curlen < 64) {
            md->md5.buf[md->md5.curlen++] = (unsigned char)0;
        }
        md5_compress(md, md->md5.buf);
        md->md5.curlen = 0;
    }

    /* pad upto 56 bytes of zeroes */
    while (md->md5.curlen < 56) {
        md->md5.buf[md->md5.curlen++] = (unsigned char)0;
    }

    /* store length */
    STORE64L(md->md5.length, md->md5.buf+56);
    md5_compress(md, md->md5.buf);

    /* copy output */
    for (i = 0; i < 4; i++) {
        STORE32L(md->md5.state[i], hash+(4*i));
    }
#ifdef CLEAN_STACK
    zeromem(md, sizeof(hash_state));
#endif
    return CRYPT_OK;
}

int  md5_test(void)
{
 #ifndef LTC_TEST
    return CRYPT_NOP;
 #else    
  static const struct {
      char *msg;
      unsigned char hash[16];
  } tests[] = {
    { "",
      { 0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04, 
        0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e } },
    { "a",
      {0x0c, 0xc1, 0x75, 0xb9, 0xc0, 0xf1, 0xb6, 0xa8, 
       0x31, 0xc3, 0x99, 0xe2, 0x69, 0x77, 0x26, 0x61 } },
    { "abc",
      { 0x90, 0x01, 0x50, 0x98, 0x3c, 0xd2, 0x4f, 0xb0, 
        0xd6, 0x96, 0x3f, 0x7d, 0x28, 0xe1, 0x7f, 0x72 } },
    { "message digest", 
      { 0xf9, 0x6b, 0x69, 0x7d, 0x7c, 0xb7, 0x93, 0x8d, 
        0x52, 0x5a, 0x2f, 0x31, 0xaa, 0xf1, 0x61, 0xd0 } }, 
    { "abcdefghijklmnopqrstuvwxyz",
      { 0xc3, 0xfc, 0xd3, 0xd7, 0x61, 0x92, 0xe4, 0x00, 
        0x7d, 0xfb, 0x49, 0x6c, 0xca, 0x67, 0xe1, 0x3b } },
    { "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
      { 0xd1, 0x74, 0xab, 0x98, 0xd2, 0x77, 0xd9, 0xf5, 
        0xa5, 0x61, 0x1c, 0x2c, 0x9f, 0x41, 0x9d, 0x9f } },
    { "12345678901234567890123456789012345678901234567890123456789012345678901234567890",
      { 0x57, 0xed, 0xf4, 0xa2, 0x2b, 0xe3, 0xc9, 0x55, 
        0xac, 0x49, 0xda, 0x2e, 0x21, 0x07, 0xb6, 0x7a } }, 
    { NULL, { 0 } }
  };

  int i;
  unsigned char tmp[16];
  hash_state md;

  for (i = 0; tests[i].msg != NULL; i++) {
      md5_init(&md);
      md5_process(&md, (unsigned char *)tests[i].msg, (unsigned long)strlen(tests[i].msg));
      md5_done(&md, tmp);
      if (memcmp(tmp, tests[i].hash, 16) != 0) {
         return CRYPT_FAIL_TESTVECTOR;
      }
  }
  return CRYPT_OK;
 #endif
}

#endif