/*

* (C) 2015 Jack Lloyd

*

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

*/

#ifndef BOTAN_PK_OPERATION_IMPL_H_

#define BOTAN_PK_OPERATION_IMPL_H_

#include <botan/internal/pk_ops.h>

#include <botan/internal/eme.h>

#include <botan/kdf.h>

#include <botan/internal/emsa.h>

namespace Botan {

namespace PK_Ops {

class Encryption_with_EME : public Encryption

   {

   public:

      size_t max_input_bits() const override;

      secure_vector<uint8_t> encrypt(const uint8_t msg[], size_t msg_len,

                                  RandomNumberGenerator& rng) override;

      ~Encryption_with_EME() = default;

   protected:

      explicit Encryption_with_EME(const std::string& eme);

   private:

      virtual size_t max_raw_input_bits() const = 0;

      virtual secure_vector<uint8_t> raw_encrypt(const uint8_t msg[], size_t len,

                                              RandomNumberGenerator& rng) = 0;

      std::unique_ptr<EME> m_eme;

   };

class Decryption_with_EME : public Decryption

   {

   public:

      secure_vector<uint8_t> decrypt(uint8_t& valid_mask,

                                  const uint8_t msg[], size_t msg_len) override;

      ~Decryption_with_EME() = default;

   protected:

      explicit Decryption_with_EME(const std::string& eme);

   private:

      virtual secure_vector<uint8_t> raw_decrypt(const uint8_t msg[], size_t len) = 0;

      std::unique_ptr<EME> m_eme;

   };

class Verification_with_EMSA : public Verification

   {

   public:

      ~Verification_with_EMSA() = default;

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

      bool is_valid_signature(const uint8_t sig[], size_t sig_len) override;

   protected:

      explicit Verification_with_EMSA(const std::string& emsa, bool has_message_recovery = false);

      std::string hash_for_signature() { return m_hash; }

      /**

      * Get the maximum message size in bits supported by this public key.

      * @return maximum message in bits

      */

      virtual size_t max_input_bits() const = 0;

      /**

      * @return boolean specifying if this signature scheme uses

      * a message prefix returned by message_prefix()

      */

      virtual bool has_prefix() { return false; }

      /**

      * @return the message prefix if this signature scheme uses

      * a message prefix, signaled via has_prefix()

      */

      virtual secure_vector<uint8_t> message_prefix() const { throw Invalid_State("No prefix"); }

      /**

      * @return boolean specifying if this key type supports message

      * recovery and thus if you need to call verify() or verify_mr()

      */

      virtual bool with_recovery() const = 0;

      /*

      * Perform a signature check operation

      * @param msg the message

      * @param msg_len the length of msg in bytes

      * @param sig the signature

      * @param sig_len the length of sig in bytes

      * @returns if signature is a valid one for message

      */

      virtual bool verify(const uint8_t[], size_t,

                          const uint8_t[], size_t)

         {

         throw Invalid_State("Message recovery required");

         }

      /*

      * Perform a signature operation (with message recovery)

      * Only call this if with_recovery() returns true

      * @param msg the message

      * @param msg_len the length of msg in bytes

      * @returns recovered message

      */

      virtual secure_vector<uint8_t> verify_mr(const uint8_t[], size_t)

         {

         throw Invalid_State("Message recovery not supported");

         }

      std::unique_ptr<EMSA> clone_emsa() const { return m_emsa->new_object(); }

   private:

      std::unique_ptr<EMSA> m_emsa;

      const std::string m_hash;

      bool m_prefix_used;

   };

class Signature_with_EMSA : public Signature

   {

   public:

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

      secure_vector<uint8_t> sign(RandomNumberGenerator& rng) override;

   protected:

      explicit Signature_with_EMSA(const std::string& emsa, bool with_message_recovery = false);

      ~Signature_with_EMSA() = default;

      std::string hash_for_signature() { return m_hash; }

      /**

      * @return boolean specifying if this signature scheme uses

      * a message prefix returned by message_prefix()

      */

      virtual bool has_prefix() { return false; }

      /**

      * @return the message prefix if this signature scheme uses

      * a message prefix, signaled via has_prefix()

      */

      virtual secure_vector<uint8_t> message_prefix() const { throw Invalid_State("No prefix"); }

      std::unique_ptr<EMSA> clone_emsa() const { return m_emsa->new_object(); }

   private:

      /**

      * Get the maximum message size in bits supported by this public key.

      * @return maximum message in bits

      */

      virtual size_t max_input_bits() const = 0;

      virtual secure_vector<uint8_t> raw_sign(const uint8_t msg[], size_t msg_len,

                                           RandomNumberGenerator& rng) = 0;

      std::unique_ptr<EMSA> m_emsa;

      const std::string m_hash;

      bool m_prefix_used;

   };

class Key_Agreement_with_KDF : public Key_Agreement

   {

   public:

      secure_vector<uint8_t> agree(size_t key_len,

                                const uint8_t other_key[], size_t other_key_len,

                                const uint8_t salt[], size_t salt_len) override;

   protected:

      explicit Key_Agreement_with_KDF(const std::string& kdf);

      ~Key_Agreement_with_KDF() = default;

   private:

      virtual secure_vector<uint8_t> raw_agree(const uint8_t w[], size_t w_len) = 0;

      std::unique_ptr<KDF> m_kdf;

   };

class KEM_Encryption_with_KDF : public KEM_Encryption

   {

   public:

      void kem_encrypt(secure_vector<uint8_t>& out_encapsulated_key,

                       secure_vector<uint8_t>& out_shared_key,

                       size_t desired_shared_key_len,

                       Botan::RandomNumberGenerator& rng,

                       const uint8_t salt[],

                       size_t salt_len) override;

   protected:

      virtual void raw_kem_encrypt(secure_vector<uint8_t>& out_encapsulated_key,

                                   secure_vector<uint8_t>& raw_shared_key,

                                   Botan::RandomNumberGenerator& rng) = 0;

      explicit KEM_Encryption_with_KDF(const std::string& kdf);

      ~KEM_Encryption_with_KDF() = default;

   private:

      std::unique_ptr<KDF> m_kdf;

   };

class KEM_Decryption_with_KDF : public KEM_Decryption

   {

   public:

      secure_vector<uint8_t> kem_decrypt(const uint8_t encap_key[],

                                      size_t len,

                                      size_t desired_shared_key_len,

                                      const uint8_t salt[],

                                      size_t salt_len) override;

   protected:

      virtual secure_vector<uint8_t>

      raw_kem_decrypt(const uint8_t encap_key[], size_t len) = 0;

      explicit KEM_Decryption_with_KDF(const std::string& kdf);

      ~KEM_Decryption_with_KDF() = default;

   private:

      std::unique_ptr<KDF> m_kdf;

   };

}

}

#endif