anubis.c

这是由Rinick编写的加解密函数库。最近找了不少关于加解密的C源码

    0xdca5f2aeU, 0xdda7f4a6U, 0xdea1febeU, 0xdfa3f8b6U,
    0xe0dd7a53U, 0xe1df7c5bU, 0xe2d97643U, 0xe3db704bU,
    0xe4d56273U, 0xe5d7647bU, 0xe6d16e63U, 0xe7d3686bU,
    0xe8cd4a13U, 0xe9cf4c1bU, 0xeac94603U, 0xebcb400bU,
    0xecc55233U, 0xedc7543bU, 0xeec15e23U, 0xefc3582bU,
    0xf0fd1ad3U, 0xf1ff1cdbU, 0xf2f916c3U, 0xf3fb10cbU,
    0xf4f502f3U, 0xf5f704fbU, 0xf6f10ee3U, 0xf7f308ebU,
    0xf8ed2a93U, 0xf9ef2c9bU, 0xfae92683U, 0xfbeb208bU,
    0xfce532b3U, 0xfde734bbU, 0xfee13ea3U, 0xffe338abU,
};

/**
 * The round constants.
 */
static const ulong32 rc[] = {
   0xa7d3e671U, 0xd0ac4d79U, 0x3ac991fcU, 0x1e4754bdU,
   0x8ca57afbU, 0x63b8ddd4U, 0xe5b3c5beU, 0xa9880ca2U,
   0x39df29daU, 0x2ba8cb4cU, 0x4b22aa24U, 0x4170a6f9U,
   0x5ae2b036U, 0x7de433ffU, 0x6020088bU, 0x5eab7f78U,
   0x7c2c57d2U, 0xdc6d7e0dU, 0x5394c328U,
};

#endif

 /**
    Initialize the Anubis 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
 */
#ifdef CLEAN_STACK
static int _anubis_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
#else
int  anubis_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
#endif
{
   int N, R, i, pos, r;
   ulong32 kappa[MAX_N];
   ulong32 inter[MAX_N];
   ulong32 v, K0, K1, K2, K3;

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

   /* Valid sizes (in bytes) are 16, 20, 24, 28, 32, 36, and 40. */
   if ((keylen & 3) || (keylen < 16) || (keylen > 40)) {
      return CRYPT_INVALID_KEYSIZE;
   }
   skey->anubis.keyBits = keylen*8;

   /*
    * determine the N length parameter:
    * (N.B. it is assumed that the key length is valid!)
    */
   N = skey->anubis.keyBits >> 5;

   /*
    * determine number of rounds from key size:
    */
   skey->anubis.R = R = 8 + N;

   if (num_rounds != 0 && num_rounds != skey->anubis.R) {
      return CRYPT_INVALID_ROUNDS;
   }

    /*
    * map cipher key to initial key state (mu):
    */
    for (i = 0, pos = 0; i < N; i++, pos += 4) {
      kappa[i] =
         (key[pos    ] << 24) ^
         (key[pos + 1] << 16) ^
         (key[pos + 2] <<  8) ^
         (key[pos + 3]      );
    }

   /*
    * generate R + 1 round keys:
    */
   for (r = 0; r <= R; r++) {
      /*
       * generate r-th round key K^r:
       */
      K0 = T4[(kappa[N - 1] >> 24)       ];
      K1 = T4[(kappa[N - 1] >> 16) & 0xff];
      K2 = T4[(kappa[N - 1] >>  8) & 0xff];
      K3 = T4[(kappa[N - 1]      ) & 0xff];
      for (i = N - 2; i >= 0; i--) {
         K0 = T4[(kappa[i] >> 24)       ] ^
            (T5[(K0 >> 24)       ] & 0xff000000U) ^
            (T5[(K0 >> 16) & 0xff] & 0x00ff0000U) ^
            (T5[(K0 >>  8) & 0xff] & 0x0000ff00U) ^
            (T5[(K0      ) & 0xff] & 0x000000ffU);
         K1 = T4[(kappa[i] >> 16) & 0xff] ^
            (T5[(K1 >> 24)       ] & 0xff000000U) ^
            (T5[(K1 >> 16) & 0xff] & 0x00ff0000U) ^
            (T5[(K1 >>  8) & 0xff] & 0x0000ff00U) ^
            (T5[(K1      ) & 0xff] & 0x000000ffU);
         K2 = T4[(kappa[i] >>  8) & 0xff] ^
            (T5[(K2 >> 24)       ] & 0xff000000U) ^
            (T5[(K2 >> 16) & 0xff] & 0x00ff0000U) ^
            (T5[(K2 >>  8) & 0xff] & 0x0000ff00U) ^
            (T5[(K2      ) & 0xff] & 0x000000ffU);
         K3 = T4[(kappa[i]      ) & 0xff] ^
            (T5[(K3 >> 24)       ] & 0xff000000U) ^
            (T5[(K3 >> 16) & 0xff] & 0x00ff0000U) ^
            (T5[(K3 >>  8) & 0xff] & 0x0000ff00U) ^
            (T5[(K3      ) & 0xff] & 0x000000ffU);
      }
      /*
      -- this is the code to use with the large U tables:
      K0 = K1 = K2 = K3 = 0;
      for (i = 0; i < N; i++) {
         K0 ^= U[i][(kappa[i] >> 24)       ];
         K1 ^= U[i][(kappa[i] >> 16) & 0xff];
         K2 ^= U[i][(kappa[i] >>  8) & 0xff];
         K3 ^= U[i][(kappa[i]      ) & 0xff];
      }
      */
      skey->anubis.roundKeyEnc[r][0] = K0;
      skey->anubis.roundKeyEnc[r][1] = K1;
      skey->anubis.roundKeyEnc[r][2] = K2;
      skey->anubis.roundKeyEnc[r][3] = K3;

      /*
       * compute kappa^{r+1} from kappa^r:
       */
      if (r == R) {
         break;
      }
      for (i = 0; i < N; i++) {
         int j = i;
         inter[i]  = T0[(kappa[j--] >> 24)       ]; if (j < 0) j = N - 1;
         inter[i] ^= T1[(kappa[j--] >> 16) & 0xff]; if (j < 0) j = N - 1;
         inter[i] ^= T2[(kappa[j--] >>  8) & 0xff]; if (j < 0) j = N - 1;
         inter[i] ^= T3[(kappa[j  ]      ) & 0xff];
      }
      kappa[0] = inter[0] ^ rc[r];
      for (i = 1; i < N; i++) {
         kappa[i] = inter[i];
      }
   }

   /*
    * generate inverse key schedule: K'^0 = K^R, K'^R = K^0, K'^r = theta(K^{R-r}):
    */
   for (i = 0; i < 4; i++) {
      skey->anubis.roundKeyDec[0][i] = skey->anubis.roundKeyEnc[R][i];
      skey->anubis.roundKeyDec[R][i] = skey->anubis.roundKeyEnc[0][i];
   }
   for (r = 1; r < R; r++) {
      for (i = 0; i < 4; i++) {
         v = skey->anubis.roundKeyEnc[R - r][i];
         skey->anubis.roundKeyDec[r][i] =
            T0[T4[(v >> 24)       ] & 0xff] ^
            T1[T4[(v >> 16) & 0xff] & 0xff] ^
            T2[T4[(v >>  8) & 0xff] & 0xff] ^
            T3[T4[(v      ) & 0xff] & 0xff];
      }
   }

   return CRYPT_OK;
}

#ifdef CLEAN_STACK
int  anubis_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
{
  int err;
  err = _anubis_setup(key, keylen, num_rounds, skey);
  burn_stack(sizeof(int) * 5 + sizeof(ulong32) * (MAX_N + MAX_N + 5));
  return err;
}
#endif
  

static void anubis_crypt(const unsigned char *plaintext, unsigned char *ciphertext,
                         ulong32 roundKey[18 + 1][4], int R) {
   int i, pos, r;
   ulong32 state[4];
   ulong32 inter[4];

    /*
    * map plaintext block to cipher state (mu)
    * and add initial round key (sigma[K^0]):
    */
    for (i = 0, pos = 0; i < 4; i++, pos += 4) {
      state[i] =
         (plaintext[pos    ] << 24) ^
         (plaintext[pos + 1] << 16) ^
         (plaintext[pos + 2] <<  8) ^
         (plaintext[pos + 3]      ) ^
         roundKey[0][i];
    }

    /*
     * R - 1 full rounds:
     */
    for (r = 1; r < R; r++) {
      inter[0] =
         T0[(state[0] >> 24)       ] ^
         T1[(state[1] >> 24)       ] ^
         T2[(state[2] >> 24)       ] ^
         T3[(state[3] >> 24)       ] ^
         roundKey[r][0];
      inter[1] =
         T0[(state[0] >> 16) & 0xff] ^
         T1[(state[1] >> 16) & 0xff] ^
         T2[(state[2] >> 16) & 0xff] ^
         T3[(state[3] >> 16) & 0xff] ^
         roundKey[r][1];
      inter[2] =
         T0[(state[0] >>  8) & 0xff] ^
         T1[(state[1] >>  8) & 0xff] ^
         T2[(state[2] >>  8) & 0xff] ^
         T3[(state[3] >>  8) & 0xff] ^
         roundKey[r][2];
      inter[3] =
         T0[(state[0]      ) & 0xff] ^
         T1[(state[1]      ) & 0xff] ^
         T2[(state[2]      ) & 0xff] ^
         T3[(state[3]      ) & 0xff] ^
         roundKey[r][3];
      state[0] = inter[0];
      state[1] = inter[1];
      state[2] = inter[2];
      state[3] = inter[3];
    }

    /*
    * last round:
    */
   inter[0] =
      (T0[(state[0] >> 24)       ] & 0xff000000U) ^
      (T1[(state[1] >> 24)       ] & 0x00ff0000U) ^
      (T2[(state[2] >> 24)       ] & 0x0000ff00U) ^
      (T3[(state[3] >> 24)       ] & 0x000000ffU) ^
      roundKey[R][0];
   inter[1] =
      (T0[(state[0] >> 16) & 0xff] & 0xff000000U) ^
      (T1[(state[1] >> 16) & 0xff] & 0x00ff0000U) ^
      (T2[(state[2] >> 16) & 0xff] & 0x0000ff00U) ^
      (T3[(state[3] >> 16) & 0xff] & 0x000000ffU) ^
      roundKey[R][1];
   inter[2] =
      (T0[(state[0] >>  8) & 0xff] & 0xff000000U) ^
      (T1[(state[1] >>  8) & 0xff] & 0x00ff0000U) ^
      (T2[(state[2] >>  8) & 0xff] & 0x0000ff00U) ^
      (T3[(state[3] >>  8) & 0xff] & 0x000000ffU) ^
      roundKey[R][2];
   inter[3] =
      (T0[(state[0]      ) & 0xff] & 0xff000000U) ^
      (T1[(state[1]      ) & 0xff] & 0x00ff0000U) ^
      (T2[(state[2]      ) & 0xff] & 0x0000ff00U) ^
      (T3[(state[3]      ) & 0xff] & 0x000000ffU) ^
      roundKey[R][3];

   /*
    * map cipher state to ciphertext block (mu^{-1}):
    */
    for (i = 0, pos = 0; i < 4; i++, pos += 4) {
        ulong32 w = inter[i];
        ciphertext[pos    ] = (unsigned char)(w >> 24);
        ciphertext[pos + 1] = (unsigned char)(w >> 16);
        ciphertext[pos + 2] = (unsigned char)(w >>  8);
        ciphertext[pos + 3] = (unsigned char)(w      );
    }
}

/**
  Encrypts a block of text with Anubis
  @param pt The input plaintext (16 bytes)
  @param ct The output ciphertext (16 bytes)
  @param skey The key as scheduled
*/
void anubis_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *skey)
{
   LTC_ARGCHK(pt   != NULL);
   LTC_ARGCHK(ct   != NULL);
   LTC_ARGCHK(skey != NULL);
   anubis_crypt(pt, ct, skey->anubis.roundKeyEnc, skey->anubis.R);
}

/**
  Decrypts a block of text with Anubis
  @param ct The input ciphertext (16 bytes)