/*

* Diffie-Hellman

* (C) 1999-2007,2023 Jack Lloyd

*

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

*/

#ifndef BOTAN_DIFFIE_HELLMAN_H_

#define BOTAN_DIFFIE_HELLMAN_H_

#include <botan/pk_keys.h>

#include <memory>

namespace Botan {

class BigInt;

class DL_Group;

class DL_PublicKey;

class DL_PrivateKey;

/**

* This class represents Diffie-Hellman public keys.

*/

class BOTAN_PUBLIC_API(2, 0) DH_PublicKey : public virtual Public_Key {

   public:

      /**

      * Create a public key.

      * @param alg_id the X.509 algorithm identifier

      * @param key_bits DER encoded public key bits

      */

      DH_PublicKey(const AlgorithmIdentifier& alg_id, std::span<const uint8_t> key_bits);

      /**

      * Construct a public key with the specified parameters.

      * @param group the DL group to use in the key

      * @param y the public value y

      */

      DH_PublicKey(const DL_Group& group, const BigInt& y);

      AlgorithmIdentifier algorithm_identifier() const override;

      std::vector<uint8_t> raw_public_key_bits() const override;

      std::vector<uint8_t> public_key_bits() const override;

      bool check_key(RandomNumberGenerator& rng, bool strong) const override;

      size_t estimated_strength() const override;

      size_t key_length() const override;

      std::vector<uint8_t> public_value() const;

      std::string algo_name() const override { return "DH"; }

      const BigInt& get_int_field(std::string_view field) const override;

      bool supports_operation(PublicKeyOperation op) const override { return (op == PublicKeyOperation::KeyAgreement); }

      std::unique_ptr<Private_Key> generate_another(RandomNumberGenerator& rng) const final;

      const DL_Group& group() const;

   private:

      friend class DH_PrivateKey;

      DH_PublicKey() = default;

      DH_PublicKey(std::shared_ptr<const DL_PublicKey> key) : m_public_key(std::move(key)) {}

      std::shared_ptr<const DL_PublicKey> m_public_key;

};

/**

* This class represents Diffie-Hellman private keys.

*/

BOTAN_DIAGNOSTIC_PUSH

BOTAN_DIAGNOSTIC_IGNORE_INHERITED_VIA_DOMINANCE

class BOTAN_PUBLIC_API(2, 0) DH_PrivateKey final : public DH_PublicKey,

                                                   public PK_Key_Agreement_Key,

                                                   public virtual Private_Key {

   public:

      /**

      * Load a private key from the ASN.1 encoding

      * @param alg_id the X.509 algorithm identifier

      * @param key_bits PKCS #8 structure

      */

      DH_PrivateKey(const AlgorithmIdentifier& alg_id, std::span<const uint8_t> key_bits);

      /**

      * Load a private key from the integer encoding

      * @param group the underlying DL group

      * @param private_key the private key

      */

      DH_PrivateKey(const DL_Group& group, const BigInt& private_key);

      /**

      * Create a new private key.

      * @param group the underlying DL group

      * @param rng the RNG to use

      */

      DH_PrivateKey(RandomNumberGenerator& rng, const DL_Group& group);

      std::unique_ptr<Public_Key> public_key() const override;

      std::vector<uint8_t> public_value() const override;

      secure_vector<uint8_t> private_key_bits() const override;

      secure_vector<uint8_t> raw_private_key_bits() const override;

      const BigInt& get_int_field(std::string_view field) const override;

      std::unique_ptr<PK_Ops::Key_Agreement> create_key_agreement_op(RandomNumberGenerator& rng,

                                                                     std::string_view params,

                                                                     std::string_view provider) const override;

   private:

      std::shared_ptr<const DL_PrivateKey> m_private_key;

};

BOTAN_DIAGNOSTIC_POP

}  // namespace Botan

#endif