blowfish.c

该压缩包中包括 tom的加密函数库及pdf说明 ,以及Rinick s ECC：椭圆曲线非对称加密密钥生成器

        0x1948C25CUL, 0x02FB8A8CUL, 0x01C36AE4UL, 0xD6EBE1F9UL,
        0x90D4F869UL, 0xA65CDEA0UL, 0x3F09252DUL, 0xC208E69FUL,
        0xB74E6132UL, 0xCE77E25BUL, 0x578FDFE3UL, 0x3AC372E6UL  }
};

 /**
    Initialize the Blowfish block cipher
    @param key The symmetric key you wish to pass
    @param keylen The key length in bytes
    @param num_rounds The number of rounds desired (0 for default)
    @param skey The key in as scheduled by this function.
    @return CRYPT_OK if successful
 */
int blowfish_setup(const unsigned char *key, int keylen, int num_rounds,
                   symmetric_key *skey)
{
   ulong32 x, y, z, A;
   unsigned char B[8];

   LTC_ARGCHK(key != NULL);
   LTC_ARGCHK(skey != NULL);

   /* check key length */
   if (keylen < 8 || keylen > 56) {
      return CRYPT_INVALID_KEYSIZE;
   }

   /* check rounds */
   if (num_rounds != 0 && num_rounds != 16) {
      return CRYPT_INVALID_ROUNDS;
   }   

   /* load in key bytes (Supplied by David Hopwood) */
   for (x = y = 0; x < 18; x++) {
       A = 0;
       for (z = 0; z < 4; z++) {
           A = (A << 8) | ((ulong32)key[y++] & 255);
           if (y == (ulong32)keylen) { 
              y = 0; 
           }
       }
       skey->blowfish.K[x] = ORIG_P[x] ^ A;
   }

   /* copy sboxes */
   for (x = 0; x < 4; x++) {
       for (y = 0; y < 256; y++) {
           skey->blowfish.S[x][y] = ORIG_S[x][y];
       }
   }

   /* encrypt K array */
   for (x = 0; x < 8; x++) {
       B[x] = 0;
   }
   
   for (x = 0; x < 18; x += 2) {
       /* encrypt it */
       blowfish_ecb_encrypt(B, B, skey);
       /* copy it */
       LOAD32H(skey->blowfish.K[x], &B[0]);
       LOAD32H(skey->blowfish.K[x+1], &B[4]);
   }

   /* encrypt S array */
   for (x = 0; x < 4; x++) {
       for (y = 0; y < 256; y += 2) {
          /* encrypt it */
          blowfish_ecb_encrypt(B, B, skey);
          /* copy it */
          LOAD32H(skey->blowfish.S[x][y], &B[0]);
          LOAD32H(skey->blowfish.S[x][y+1], &B[4]);
       }
   }

#ifdef LTC_CLEAN_STACK
   zeromem(B, sizeof(B));
#endif

   return CRYPT_OK;
}

#ifndef __GNUC__
#define F(x) ((S1[byte(x,3)] + S2[byte(x,2)]) ^ S3[byte(x,1)]) + S4[byte(x,0)]
#else
#define F(x) ((skey->blowfish.S[0][byte(x,3)] + skey->blowfish.S[1][byte(x,2)]) ^ skey->blowfish.S[2][byte(x,1)]) + skey->blowfish.S[3][byte(x,0)]
#endif

/**
  Encrypts a block of text with Blowfish
  @param pt The input plaintext (8 bytes)
  @param ct The output ciphertext (8 bytes)
  @param skey The key as scheduled
*/
#ifdef LTC_CLEAN_STACK
static void _blowfish_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
#else
void blowfish_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
#endif
{
   ulong32 L, R;
   int r;
#ifndef __GNUC__
   ulong32 *S1, *S2, *S3, *S4;
#endif

    LTC_ARGCHK(pt   != NULL);
    LTC_ARGCHK(ct   != NULL);
    LTC_ARGCHK(skey != NULL);

#ifndef __GNUC__
    S1 = skey->blowfish.S[0];
    S2 = skey->blowfish.S[1];
    S3 = skey->blowfish.S[2];
    S4 = skey->blowfish.S[3];
#endif

   /* load it */
   LOAD32H(L, &pt[0]);
   LOAD32H(R, &pt[4]);

   /* do 16 rounds */
   for (r = 0; r < 16; ) {
      L ^= skey->blowfish.K[r++];  R ^= F(L);
      R ^= skey->blowfish.K[r++];  L ^= F(R);
      L ^= skey->blowfish.K[r++];  R ^= F(L);
      R ^= skey->blowfish.K[r++];  L ^= F(R);
   }

   /* last keying */
   R ^= skey->blowfish.K[17];
   L ^= skey->blowfish.K[16];

   /* store */
   STORE32H(R, &ct[0]);
   STORE32H(L, &ct[4]);
}

#ifdef LTC_CLEAN_STACK
void blowfish_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
{
    _blowfish_ecb_encrypt(pt, ct, skey);
    burn_stack(sizeof(ulong32) * 2 + sizeof(int));
}
#endif

/**
  Decrypts a block of text with Blowfish
  @param ct The input ciphertext (8 bytes)
  @param pt The output plaintext (8 bytes)
  @param skey The key as scheduled 
*/
#ifdef LTC_CLEAN_STACK
static void _blowfish_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
#else
void blowfish_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
#endif
{
   ulong32 L, R;
   int r;
#ifndef __GNUC__
   ulong32 *S1, *S2, *S3, *S4;
#endif

    LTC_ARGCHK(pt   != NULL);
    LTC_ARGCHK(ct   != NULL);
    LTC_ARGCHK(skey != NULL);
    
#ifndef __GNUC__
    S1 = skey->blowfish.S[0];
    S2 = skey->blowfish.S[1];
    S3 = skey->blowfish.S[2];
    S4 = skey->blowfish.S[3];
#endif

   /* load it */
   LOAD32H(R, &ct[0]);
   LOAD32H(L, &ct[4]);

   /* undo last keying */
   R ^= skey->blowfish.K[17];
   L ^= skey->blowfish.K[16];

   /* do 16 rounds */
   for (r = 15; r > 0; ) {
      L ^= F(R); R ^= skey->blowfish.K[r--];
      R ^= F(L); L ^= skey->blowfish.K[r--];
      L ^= F(R); R ^= skey->blowfish.K[r--];
      R ^= F(L); L ^= skey->blowfish.K[r--];
   }

   /* store */
   STORE32H(L, &pt[0]);
   STORE32H(R, &pt[4]);
}

#ifdef LTC_CLEAN_STACK
void blowfish_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *skey)
{
    _blowfish_ecb_decrypt(ct, pt, skey);
    burn_stack(sizeof(ulong32) * 2 + sizeof(int));
}
#endif


/**
  Performs a self-test of the Blowfish block cipher
  @return CRYPT_OK if functional, CRYPT_NOP if self-test has been disabled
*/
int blowfish_test(void)
{
 #ifndef LTC_TEST
    return CRYPT_NOP;
 #else    
   int err;
   symmetric_key key;
   static const struct {
          unsigned char key[8], pt[8], ct[8];
   } tests[] = {
       {
           { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
           { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
           { 0x4E, 0xF9, 0x97, 0x45, 0x61, 0x98, 0xDD, 0x78}
       },
       {
           { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},
           { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},
           { 0x51, 0x86, 0x6F, 0xD5, 0xB8, 0x5E, 0xCB, 0x8A}
       },
       {
           { 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
           { 0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01},
           { 0x7D, 0x85, 0x6F, 0x9A, 0x61, 0x30, 0x63, 0xF2}
       }
   };
   unsigned char tmp[2][8];
   int x, y;

   for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) {
      /* setup key */
      if ((err = blowfish_setup(tests[x].key, 8, 16, &key)) != CRYPT_OK) {
         return err;
      }

      /* encrypt and decrypt */
      blowfish_ecb_encrypt(tests[x].pt, tmp[0], &key);
      blowfish_ecb_decrypt(tmp[0], tmp[1], &key);

      /* compare */
      if ((memcmp(tmp[0], tests[x].ct, 8) != 0) || (memcmp(tmp[1], tests[x].pt, 8) != 0)) {
         return CRYPT_FAIL_TESTVECTOR;
      }

      /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */
      for (y = 0; y < 8; y++) tmp[0][y] = 0;
      for (y = 0; y < 1000; y++) blowfish_ecb_encrypt(tmp[0], tmp[0], &key);
      for (y = 0; y < 1000; y++) blowfish_ecb_decrypt(tmp[0], tmp[0], &key);
      for (y = 0; y < 8; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR;
   }
   return CRYPT_OK;
 #endif
}

/** Terminate the context 
   @param skey    The scheduled key
*/
void blowfish_done(symmetric_key *skey)
{
}

/**
  Gets suitable key size
  @param keysize [in/out] The length of the recommended key (in bytes).  This function will store the suitable size back in this variable.
  @return CRYPT_OK if the input key size is acceptable.
*/
int blowfish_keysize(int *keysize)
{
   LTC_ARGCHK(keysize != NULL);

   if (*keysize < 8) {
      return CRYPT_INVALID_KEYSIZE;
   } else if (*keysize > 56) {
      *keysize = 56;
   }
   return CRYPT_OK;
}

#endif


/* $Source: /cvs/libtom/libtomcrypt/src/ciphers/blowfish.c,v $ */
/* $Revision: 1.7 $ */
/* $Date: 2005/05/05 14:35:58 $ */