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/*

* (C) 2018 Jack Lloyd

* Botan is released under the Simplified BSD License (see license.txt)

*/

#ifndef BOTAN_POINT_MUL_H_

#define BOTAN_POINT_MUL_H_

#include <botan/point_gfp.h>

namespace Botan {

class Modular_Reducer;

class PointGFp_Base_Point_Precompute final

   public:

      PointGFp_Base_Point_Precompute(const PointGFp& base_point,

                                     const Modular_Reducer& mod_order);

      PointGFp mul(const BigInt& k,

                   RandomNumberGenerator& rng,

                   const BigInt& group_order,

                   std::vector<BigInt>& ws) const;

   private:

      const PointGFp& m_base_point;

      const Modular_Reducer& m_mod_order;

      enum { WINDOW_BITS = 3 };

      enum { WINDOW_SIZE = (1 << WINDOW_BITS) - 1 };

      const size_t m_p_words;

/*

      * This is a table of T_size * 3*p_word words

*/

      std::vector<word> m_W;

};

class PointGFp_Var_Point_Precompute final

   public:

      PointGFp_Var_Point_Precompute(const PointGFp& point,

                                    RandomNumberGenerator& rng,

                                    std::vector<BigInt>& ws);

      PointGFp mul(const BigInt& k,

                   RandomNumberGenerator& rng,

                   const BigInt& group_order,

                   std::vector<BigInt>& ws) const;

   private:

      const CurveGFp m_curve;

      const size_t m_p_words;

      const size_t m_window_bits;

/*

      * Table of 2^window_bits * 3*2*p_word words

      * Kept in locked vector since the base point might be sensitive

      * (normally isn't in most protocols but hard to say anything

      * categorically.)

*/

      secure_vector<word> m_T;

};

class PointGFp_Multi_Point_Precompute final

   public:

      PointGFp_Multi_Point_Precompute(const PointGFp& g1,

                                      const PointGFp& g2);

/*

      * Return (g1*k1 + g2*k2)

      * Not constant time, intended to use with public inputs

*/

      PointGFp multi_exp(const BigInt& k1,

                         const BigInt& k2) const;

   private:

      std::vector<PointGFp> m_M;

      bool m_no_infinity;

};

#endif