C++ BN_is_bit_set函數代碼示例

static int
bn_rand_range(int pseudo, BIGNUM *r, BIGNUM *range)
{
    int (*bn_rand)(BIGNUM *, int, int, int) = pseudo ? BN_pseudo_rand : BN_rand;
    int n;

    if (range->neg || BN_is_zero(range)) return 0;

    n = BN_num_bits(range);

    if (n == 1) {
	if (!BN_zero(r)) return 0;
    } else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) {
	do {
	    if (!bn_rand(r, n + 1, -1, 0)) return 0;
	    if (BN_cmp(r ,range) >= 0) {
		if (!BN_sub(r, r, range)) return 0;
		if (BN_cmp(r, range) >= 0)
		    if (!BN_sub(r, r, range)) return 0;
	    }
	} while (BN_cmp(r, range) >= 0);
    } else {
	do {
	    if (!bn_rand(r, n, -1, 0)) return 0;
	} while (BN_cmp(r, range) >= 0);
    }

    return 1;
}

int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive,
                     const BIGNUM *max_exclusive, RAND *rng) {
  unsigned n;
  unsigned count = 100;

  if (BN_cmp_word(max_exclusive, min_inclusive) <= 0) {
    OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE);
    return 0;
  }

  n = BN_num_bits(max_exclusive); /* n > 0 */

  /* BN_is_bit_set(range, n - 1) always holds */
  if (n == 1) {
    BN_zero(r);
    return 1;
  }

  do {
    if (!--count) {
      OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS);
      return 0;
    }

    if (!BN_is_bit_set(max_exclusive, n - 2) &&
        !BN_is_bit_set(max_exclusive, n - 3)) {
      /* range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer
       * than range. This is a common scenario when generating a random value
       * modulo an RSA public modulus, e.g. for RSA base blinding. */
      if (!BN_rand(r, n + 1, -1 /* don't set most significant bits */,
                   0 /* don't set least significant bits */, rng)) {
        return 0;
      }

      /* If r < 3*range, use r := r MOD range (which is either r, r - range, or
       * r - 2*range). Otherwise, iterate again. Since 3*range = 11..._2, each
       * iteration succeeds with probability >= .75. */
      if (BN_cmp(r, max_exclusive) >= 0) {
        if (!BN_sub(r, r, max_exclusive)) {
          return 0;
        }
        if (BN_cmp(r, max_exclusive) >= 0) {
          if (!BN_sub(r, r, max_exclusive)) {
            return 0;
          }
        }
      }
    } else {
      /* range = 11..._2  or  range = 101..._2 */
      if (!BN_rand(r, n, -1, 0, rng)) {
        return 0;
      }
    }
  } while (BN_cmp_word(r, min_inclusive) < 0 ||
           BN_cmp(r, max_exclusive) >= 0);

  return 1;
}

int BN_rand_range(BIGNUM *r, const BIGNUM *range) {
  unsigned n;
  unsigned count = 100;

  if (range->neg || BN_is_zero(range)) {
    OPENSSL_PUT_ERROR(BN, BN_rand_range, BN_R_INVALID_RANGE);
    return 0;
  }

  n = BN_num_bits(range); /* n > 0 */

  /* BN_is_bit_set(range, n - 1) always holds */
  if (n == 1) {
    BN_zero(r);
  } else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) {
    /* range = 100..._2,
     * so  3*range (= 11..._2)  is exactly one bit longer than  range */
    do {
      if (!BN_rand(r, n + 1, -1 /* don't set most significant bits */,
                   0 /* don't set least significant bits */)) {
        return 0;
      }

      /* If r < 3*range, use r := r MOD range (which is either r, r - range, or
       * r - 2*range). Otherwise, iterate again. Since 3*range = 11..._2, each
       * iteration succeeds with probability >= .75. */
      if (BN_cmp(r, range) >= 0) {
        if (!BN_sub(r, r, range)) {
          return 0;
        }
        if (BN_cmp(r, range) >= 0) {
          if (!BN_sub(r, r, range)) {
            return 0;
          }
        }
      }

      if (!--count) {
        OPENSSL_PUT_ERROR(BN, BN_rand_range, BN_R_TOO_MANY_ITERATIONS);
        return 0;
      }
    } while (BN_cmp(r, range) >= 0);
  } else {
    do {
      /* range = 11..._2  or  range = 101..._2 */
      if (!BN_rand(r, n, -1, 0)) {
        return 0;
      }

      if (!--count) {
        OPENSSL_PUT_ERROR(BN, BN_rand_range, BN_R_TOO_MANY_ITERATIONS);
        return 0;
      }
    } while (BN_cmp(r, range) >= 0);
  }

  return 1;
}

void
dh_gen_key(DH *dh, int need)
{
	int i, bits_set, tries = 0;

	if (dh->p == NULL)
		fatal("dh_gen_key: dh->p == NULL");
	if (need > INT_MAX / 2 || 2 * need >= BN_num_bits(dh->p))
		fatal("dh_gen_key: group too small: %d (2*need %d)",
		    BN_num_bits(dh->p), 2*need);
	do {
		if (dh->priv_key != NULL)
			BN_clear_free(dh->priv_key);
		if ((dh->priv_key = BN_new()) == NULL)
			fatal("dh_gen_key: BN_new failed");
		/* generate a 2*need bits random private exponent */
		if (!BN_rand(dh->priv_key, 2*need, 0, 0))
			fatal("dh_gen_key: BN_rand failed");
		if (DH_generate_key(dh) == 0)
			fatal("DH_generate_key");
		for (i = 0, bits_set = 0; i <= BN_num_bits(dh->priv_key); i++)
			if (BN_is_bit_set(dh->priv_key, i))
				bits_set++;
		debug2("dh_gen_key: priv key bits set: %d/%d",
		    bits_set, BN_num_bits(dh->priv_key));
		if (tries++ > 10)
			fatal("dh_gen_key: too many bad keys: giving up");
	} while (!dh_pub_is_valid(dh, dh->pub_key));
}

void compute_y(BIGNUM *bn_y, BIGNUM *bn_a, BIGNUM *bn_r, BIGNUM *bn_n, BN_CTX *bn_ctx){
	BIGNUM *bn_i = NULL;
	BIGNUM *bn_1 = NULL;
	int num_bits = 0;
	int i = 0;
	BIGNUM **bn_array = NULL;
	
	num_bits = BN_num_bits(bn_r);
	bn_array = (BIGNUM **)malloc(sizeof(BIGNUM*) * num_bits);
	computeBNArray(bn_array, bn_a, bn_n, bn_ctx, num_bits);
	
	bn_1 = BN_new();
	bn_i = BN_new();
	BN_one(bn_1);
	BN_zero(bn_i);
	BN_one(bn_y);
	
	for(i = 0; i < num_bits; i++){
		if(BN_is_bit_set(bn_r, i) == 1){
			BN_mod_mul(bn_y, bn_y, bn_array[i], bn_n, bn_ctx);
		}
	}
	BN_free(bn_1);
	BN_free(bn_i);
}

int BN_exp(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, BN_CTX *ctx) {
  int i, bits, ret = 0;
  BIGNUM *v, *rr;

  if ((p->flags & BN_FLG_CONSTTIME) != 0) {
    /* BN_FLG_CONSTTIME only supported by BN_mod_exp_mont() */
    OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);
    return 0;
  }

  BN_CTX_start(ctx);
  if (r == a || r == p) {
    rr = BN_CTX_get(ctx);
  } else {
    rr = r;
  }

  v = BN_CTX_get(ctx);
  if (rr == NULL || v == NULL) {
    goto err;
  }

  if (BN_copy(v, a) == NULL) {
    goto err;
  }
  bits = BN_num_bits(p);

  if (BN_is_odd(p)) {
    if (BN_copy(rr, a) == NULL) {
      goto err;
    }
  } else {
    if (!BN_one(rr)) {
      goto err;
    }
  }

  for (i = 1; i < bits; i++) {
    if (!BN_sqr(v, v, ctx)) {
      goto err;
    }
    if (BN_is_bit_set(p, i)) {
      if (!BN_mul(rr, rr, v, ctx)) {
        goto err;
      }
    }
  }

  if (r != rr && !BN_copy(r, rr)) {
    goto err;
  }
  ret = 1;

err:
  BN_CTX_end(ctx);
  return ret;
}

/**
 * public static native void modifyBit(int, int, int)
 */
static jboolean NativeBN_modifyBit(JNIEnv* env, jclass cls, BIGNUM* a, int n, int op) {
// LOGD("NativeBN_BN_modifyBit");
    if (!oneValidHandle(env, a)) return FALSE;
    switch (op) {
    case 1: return BN_set_bit(a, n);
    case 0: return BN_clear_bit(a, n);
    case -1:
        if (BN_is_bit_set(a, n)) return BN_clear_bit(a, n);
        else return BN_set_bit(a, n);
    }
    return FALSE;
}

/*
 * call-seq:
 *    bn.bit_set?(bit) => true | false
 */
static VALUE
ossl_bn_is_bit_set(VALUE self, VALUE bit)
{
    int b;
    BIGNUM *bn;

    b = NUM2INT(bit);
    GetBN(self, bn);
    if (BN_is_bit_set(bn, b)) {
	return Qtrue;
    }
    return Qfalse;
}

int BN_bn2solinas(const BIGNUM *bn, BN_SOLINAS *solinas)
{
	int ret = 0;
	BIGNUM *tmp = NULL;
	int nbits;
	int i;

	if (!solinas || !bn) {
		BNerr(BN_F_BN_BN2SOLINAS, ERR_R_PASSED_NULL_PARAMETER);
		return 0;
	}

	if (!BN_copy(tmp, bn)) {
		goto end;
	}

	if ((nbits = BN_num_bits(bn) - 1) < 1) {
		BNerr(BN_F_BN_BN2SOLINAS, BN_R_INVALID_SOLINAS);
		goto end;
	}

	solinas->c = BN_is_bit_set(bn, 1) ? 1 : -1;

	if (BN_is_bit_set(bn, nbits - 1)) {
		solinas->s = -1;
		solinas->a = nbits;
	} else {
		solinas->s = 1;
		solinas->a = nbits - 1;
	}

	for (i = 1; i < nbits; i++) {
	}

end:
	return ret;
}

/* random number r:  0 <= r < range */
int	BN_rand_range(BIGNUM *r, BIGNUM *range)
	{
	int n;

	if (range->neg || BN_is_zero(range))
		{
		BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE);
		return 0;
		}

	n = BN_num_bits(range); /* n > 0 */

	if (n == 1)
		{
		if (!BN_zero(r)) return 0;
		}
	else if (BN_is_bit_set(range, n - 2))
		{
		do
			{
			/* range = 11..._2, so each iteration succeeds with probability >= .75 */
			if (!BN_rand(r, n, -1, 0)) return 0;
			}
		while (BN_cmp(r, range) >= 0);
		}
	else
		{
		/* range = 10..._2,
		 * so  3*range (= 11..._2)  is exactly one bit longer than  range */
		do
			{
			if (!BN_rand(r, n + 1, -1, 0)) return 0;
			/* If  r < 3*range,  use  r := r MOD range
			 * (which is either  r, r - range,  or  r - 2*range).
			 * Otherwise, iterate once more.
			 * Since  3*range = 11..._2, each iteration succeeds with
			 * probability >= .75. */
			if (BN_cmp(r ,range) >= 0)
				{
				if (!BN_sub(r, r, range)) return 0;
				if (BN_cmp(r, range) >= 0)
					if (!BN_sub(r, r, range)) return 0;
				}
			}
		while (BN_cmp(r, range) >= 0);
		}

	return 1;
	}

int bn_probable_prime_dh_coprime(BIGNUM *rnd, int bits, BN_CTX *ctx)
{
    int i;
    BIGNUM *offset_index;
    BIGNUM *offset_count;
    int ret = 0;

    OPENSSL_assert(bits > prime_multiplier_bits);

    BN_CTX_start(ctx);
    if ((offset_index = BN_CTX_get(ctx)) == NULL)
        goto err;
    if ((offset_count = BN_CTX_get(ctx)) == NULL)
        goto err;

    if (!BN_add_word(offset_count, prime_offset_count))
        goto err;

 loop:
    if (!BN_rand(rnd, bits - prime_multiplier_bits,
                 BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD))
        goto err;
    if (BN_is_bit_set(rnd, bits))
        goto loop;
    if (!BN_rand_range(offset_index, offset_count))
        goto err;

    if (!BN_mul_word(rnd, prime_multiplier)
        || !BN_add_word(rnd, prime_offsets[BN_get_word(offset_index)]))
        goto err;

    /* we now have a random number 'rand' to test. */

    /* skip coprimes */
    for (i = first_prime_index; i < NUMPRIMES; i++) {
        /* check that rnd is a prime */
        BN_ULONG mod = BN_mod_word(rnd, (BN_ULONG)primes[i]);
        if (mod == (BN_ULONG)-1)
            goto err;
        if (mod <= 1)
            goto loop;
    }
    ret = 1;

 err:
    BN_CTX_end(ctx);
    bn_check_top(rnd);
    return ret;
}

int
dh_pub_is_valid(const DH *dh, const BIGNUM *dh_pub)
{
	int i;
	int n = BN_num_bits(dh_pub);
	int bits_set = 0;
	BIGNUM *tmp;
	const BIGNUM *p;

	if (BN_is_negative(dh_pub)) {
		logit("invalid public DH value: negative");
		return 0;
	}
	if (BN_cmp(dh_pub, BN_value_one()) != 1) {	/* pub_exp <= 1 */
		logit("invalid public DH value: <= 1");
		return 0;
	}

	if ((tmp = BN_new()) == NULL) {
		error("%s: BN_new failed", __func__);
		return 0;
	}
	DH_get0_pqg(dh, &p, NULL, NULL);
	if (!BN_sub(tmp, p, BN_value_one()) ||
	    BN_cmp(dh_pub, tmp) != -1) {		/* pub_exp > p-2 */
		BN_clear_free(tmp);
		logit("invalid public DH value: >= p-1");
		return 0;
	}
	BN_clear_free(tmp);

	for (i = 0; i <= n; i++)
		if (BN_is_bit_set(dh_pub, i))
			bits_set++;
	debug2("bits set: %d/%d", bits_set, BN_num_bits(p));

	/*
	 * if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial
	 */
	if (bits_set < 4) {
		logit("invalid public DH value (%d/%d)",
		   bits_set, BN_num_bits(p));
		return 0;
	}
	return 1;
}

int dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
{
	int i;
	int n = BN_num_bits(dh_pub);
	int bits_set = 0;

	if (dh_pub->neg) {
		//logit("invalid public DH value: negativ");
		return 0;
	}
	for (i = 0; i <= n; i++)
		if (BN_is_bit_set(dh_pub, i))
			bits_set++;
	//debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p));

	/* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */
	if (bits_set > 1 && (BN_cmp(dh_pub, dh->p) == -1))
		return 1;
	//logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
	return 0;
}

void
print_ascii(FILE *f, const struct number *n)
{
	BIGNUM *v;
	int numbits, i, ch;

	v = BN_dup(n->number);
	bn_checkp(v);

	if (BN_cmp(v, &zero) < 0)
		bn_check(BN_sub(v, &zero, v));

	numbits = BN_num_bytes(v) * 8;
	while (numbits > 0) {
		ch = 0;
		for (i = 0; i < 8; i++)
			ch |= BN_is_bit_set(v, numbits-i-1) << (7 - i);
		putc(ch, f);
		numbits -= 8;
	}
	BN_free(v);
}

void
fixed_mod_exp (auto_BN & retval,
               const auto_BN & base,
               const auto_BN & exp,
               const auto_BN & modulus,
               auto_BN_CTX & ctx)
{
#if defined (MOD_EXP_STATS)
   clock_t start_time = clock();
#endif

   // Number of bits in the exponent
   int numbits = BN_num_bits(exp);

   // An iterator to search the map
   std::map< g_base_mod_pair, g_bn_vec >::iterator m_it;
   // The values corresponding to our base
   g_bn_vec current_vector;
   // Try to find base in map

   VHUtil::AutoMutex m(g_mutex);
   m_it = g_fme_map.find(g_base_mod_pair(base, modulus));
   {
      // Make a mutex object to keep the map in one thread at a time

      if (m_it != g_fme_map.end() )
      {
         // Found it
         current_vector = m_it->second;
         if (current_vector.size() < numbits )
         {
            // Need more bits in the vector
            for (int n=current_vector.size(); n<numbits; n++)
            {
               // The final table value
               auto_BN t_value;
               if ( !(BN_mod_mul(t_value, current_vector[n-1], current_vector[n-1],
                  modulus, ctx)) )
                  throw SSL_ERROR;
               current_vector.push_back(t_value);
            }
         }
      }
      else
      {
         // Didn't find it, create the table values and put into a new vector
         std::vector< auto_BN > table_values;
         // Seed our table with the base^(2^0)
         table_values.push_back(base);

         for (int i=1; i<numbits; i++)
         {
            // The final table value
            auto_BN t_value;
            if ( !(BN_mod_mul(t_value, table_values[i-1], table_values[i-1],
               modulus, ctx)) )
               throw SSL_ERROR;
            table_values.push_back(t_value);
         }
         current_vector = table_values;
         // Add the base and vector to our map
         g_fme_map.insert(std::pair< g_base_mod_pair, g_bn_vec >
            (g_base_mod_pair(base, modulus), current_vector));
      }
   }

   // Now look up the exponent
   // Our running product
   auto_BN prod_values;
   BN_one(prod_values);
   for (int j=0; j<numbits; j++)
   {
      // Find out which bits are set, then find those
      // values in the vector and multiply them together
      if (BN_is_bit_set(exp, j) != 0)
      {
         // The bit is set, so find the value in the vector and multiply
         if ( !(BN_mod_mul(prod_values, prod_values, current_vector[j], modulus, ctx)) )
            throw SSL_ERROR;
      }
   }

   retval = prod_values;

#if defined (MOD_EXP_STATS)
   time_spent_in_fme += clock() - start_time;

   {
      auto_BN alternate_retval;
      clock_t start_time = clock();
      BN_mod_exp(alternate_retval, base, exp, modulus, ctx);
      time_spent_in_BN_mod_exp += clock() - start_time;
      VH_zero(BN_cmp(alternate_retval, retval), FIXED_MOD_EXP_SCREWED_UP);
   }
#endif
}