/*

* X9.31 EMSA

* (C) 1999-2007 Jack Lloyd

*

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

*/

#ifndef BOTAN_EMSA_X931_H_

#define BOTAN_EMSA_X931_H_

#include <botan/internal/emsa.h>

#include <botan/hash.h>

namespace Botan {

/**

* EMSA from X9.31 (EMSA2 in IEEE 1363)

* Useful for Rabin-Williams, also sometimes used with RSA in

* odd protocols.

*/

class EMSA_X931 final : public EMSA

   {

   public:

      /**

      * @param hash the hash function to use

      */

      explicit EMSA_X931(std::unique_ptr<HashFunction> hash);

      std::unique_ptr<EMSA> new_object() override { return std::make_unique<EMSA_X931>(m_hash->new_object()); }

      std::string name() const override;

      bool requires_message_recovery() const override { return true; }

   private:

      void update(const uint8_t[], size_t) override;

      secure_vector<uint8_t> raw_data() override;

      secure_vector<uint8_t> encoding_of(const secure_vector<uint8_t>&, size_t,

                                     RandomNumberGenerator& rng) override;

      bool verify(const secure_vector<uint8_t>&, const secure_vector<uint8_t>&,

                  size_t) override;

      secure_vector<uint8_t> m_empty_hash;

      std::unique_ptr<HashFunction> m_hash;

      uint8_t m_hash_id;

   };

}

#endif