C++ (Cpp) bigint_monty_redc Examples

Example #1

File: monty.cpp Project: mgierlings/botan

void Montgomery_Params::square_this(BigInt& x,
                                    secure_vector<word>& ws) const
   {
   const size_t output_size = 2*m_p_words + 2;

   if(ws.size() < 2*output_size)
      ws.resize(2*output_size);

   word* z_data = &ws[0];
   word* ws_data = &ws[output_size];

   BOTAN_DEBUG_ASSERT(x.sig_words() <= m_p_words);

   bigint_sqr(z_data, output_size,
              x.data(), x.size(), std::min(m_p_words, x.size()),
              ws_data, output_size);

   bigint_monty_redc(z_data,
                     m_p.data(), m_p_words, m_p_dash,
                     ws_data, output_size);

   if(x.size() < output_size)
      x.grow_to(output_size);
   copy_mem(x.mutable_data(), z_data, output_size);
   }

Example #2

File: monty_exp.cpp Project: noloader/botan

BigInt Montgomery_Exponentation_State::exponentiation(const BigInt& k) const
   {
   const size_t exp_nibbles = (k.bits() + m_window_bits - 1) / m_window_bits;

   BigInt x = m_R_mod;

   const size_t z_size = 2*(m_p_words + 1);

   BigInt z(BigInt::Positive, z_size);
   secure_vector<word> workspace(z.size());
   secure_vector<word> e(m_p_words);

   for(size_t i = exp_nibbles; i > 0; --i)
      {
      for(size_t j = 0; j != m_window_bits; ++j)
         {
         bigint_monty_sqr(z, x, m_p.data(), m_p_words, m_mod_prime,
                          workspace.data());

         x = z;
         }

      const uint32_t nibble = k.get_substring(m_window_bits*(i-1), m_window_bits);

      BigInt::const_time_lookup(e, m_g, nibble);

      bigint_mul(z.mutable_data(), z.size(),
                 x.data(), x.size(), x.sig_words(),
                 e.data(), m_p_words, m_p_words,
                 workspace.data());

      bigint_monty_redc(z.mutable_data(),
                        m_p.data(), m_p_words, m_mod_prime,
                        workspace.data());

      x = z;
      }

   x.grow_to(2*m_p_words + 1);

   bigint_monty_redc(x.mutable_data(),
                     m_p.data(), m_p_words, m_mod_prime,
                     workspace.data());

   return x;
   }

Example #3

File: mp_monty.cpp Project: Jesse-V/botan

void bigint_monty_sqr(word z[], size_t z_size,
                      const word x[], size_t x_size, size_t x_sw,
                      const word p[], size_t p_size, word p_dash,
                      word ws[])
   {
   bigint_sqr(&z[0], z_size, &ws[0],
              &x[0], x_size, x_sw);

   bigint_monty_redc(&z[0],
                     &p[0], p_size, p_dash,
                     &ws[0]);
   }

Example #4

File: monty.cpp Project: mgierlings/botan

BigInt Montgomery_Params::redc(const BigInt& x, secure_vector<word>& ws) const
   {
   const size_t output_size = 2*m_p_words + 2;

   if(ws.size() < output_size)
      ws.resize(output_size);

   BigInt z = x;
   z.grow_to(output_size);

   bigint_monty_redc(z.mutable_data(),
                     m_p.data(), m_p_words, m_p_dash,
                     ws.data(), ws.size());

   return z;
   }

Example #5

File: monty.cpp Project: mgierlings/botan

BigInt Montgomery_Params::sqr(const BigInt& x, secure_vector<word>& ws) const
   {
   const size_t output_size = 2*m_p_words + 2;

   if(ws.size() < output_size)
      ws.resize(output_size);

   BigInt z(BigInt::Positive, output_size);

   BOTAN_DEBUG_ASSERT(x.sig_words() <= m_p_words);

   bigint_sqr(z.mutable_data(), z.size(),
              x.data(), x.size(), std::min(m_p_words, x.size()),
              ws.data(), ws.size());

   bigint_monty_redc(z.mutable_data(),
                     m_p.data(), m_p_words, m_p_dash,
                     ws.data(), ws.size());

   return z;
   }

Example #6

File: powm_mnt.cpp Project: jurajsomorovsky/botan

/*
* Compute the result
*/
BigInt Montgomery_Exponentiator::execute() const
   {
   const size_t exp_nibbles = (m_exp_bits + m_window_bits - 1) / m_window_bits;

   BigInt x = m_R_mod;

   const size_t z_size = 2*(m_mod_words + 1);

   BigInt z(BigInt::Positive, z_size);
   secure_vector<word> workspace(z.size());

   for(size_t i = exp_nibbles; i > 0; --i)
      {
      for(size_t k = 0; k != m_window_bits; ++k)
         {
         bigint_monty_sqr(z, x, m_modulus.data(), m_mod_words, m_mod_prime,
                          workspace.data());

         x = z;
         }

      const u32bit nibble = m_exp.get_substring(m_window_bits*(i-1), m_window_bits);

      const BigInt& y = m_g[nibble];

      bigint_monty_mul(z, x, y,
                       m_modulus.data(), m_mod_words, m_mod_prime,
                       workspace.data());

      x = z;
      }

   x.grow_to(2*m_mod_words + 1);

   bigint_monty_redc(x.mutable_data(),
                     m_modulus.data(), m_mod_words, m_mod_prime,
                     workspace.data());

   return x;
   }