/*

 * Crystals Kyber key encapsulation mechanism

 * Based on the public domain reference implementation by the

 * designers (https://github.com/pq-crystals/kyber)

 *

 * Further changes

 * (C) 2021-2022 Jack Lloyd

 * (C) 2021-2022 Manuel Glaser and Michael Boric, Rohde & Schwarz Cybersecurity

 * (C) 2021-2022 René Meusel and Hannes Rantzsch, neXenio GmbH

 *

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

 */

#ifndef BOTAN_KYBER_COMMON_H_

#define BOTAN_KYBER_COMMON_H_

#include <botan/asn1_obj.h>

#include <botan/der_enc.h>

#include <botan/exceptn.h>

#include <botan/pk_keys.h>

#if !defined(BOTAN_HAS_KYBER_90S) && !defined(BOTAN_HAS_KYBER)

   static_assert(false, "botan module 'kyber_common' is useful only when enabling modules 'kyber', 'kyber_90s' or both");

#endif

namespace Botan {

class BOTAN_PUBLIC_API(3, 0) KyberMode

   {

   public:

      enum Mode

         {

         Kyber512,

         Kyber512_90s,

         Kyber768,

         Kyber768_90s,

         Kyber1024,

         Kyber1024_90s

         };

      KyberMode(Mode mode);

      explicit KyberMode(const OID& oid);

      explicit KyberMode(const std::string& str);

      OID object_identifier() const;

      std::string to_string() const;

      Mode mode() const { return m_mode; }

      bool is_90s() const { return m_mode == Kyber512_90s || m_mode == Kyber768_90s || m_mode == Kyber1024_90s; }

      bool is_modern() const { return !is_90s(); }

      bool operator==(const KyberMode& other) const { return m_mode == other.m_mode; }

      bool operator!=(const KyberMode& other) const { return !(*this == other); }

   private:

      Mode m_mode;

   };

enum class KyberKeyEncoding

   {

   Raw, // as implemented in the reference implementation

   Full // as described in draft-uni-qsckeys-00 Section 4.3 (private key), 4.5 (public key)

   };

class Kyber_PublicKeyInternal;

class Kyber_PrivateKeyInternal;

class BOTAN_PUBLIC_API(3, 0) Kyber_PublicKey : public virtual Public_Key

   {

   public:

      Kyber_PublicKey(const std::vector<uint8_t>& pub_key,

                      KyberMode mode,

                      KyberKeyEncoding encoding);

      Kyber_PublicKey(const AlgorithmIdentifier& alg_id,

                      const std::vector<uint8_t>& key_bits);

      Kyber_PublicKey(const Kyber_PublicKey& other);

      Kyber_PublicKey& operator=(const Kyber_PublicKey& other) = default;

      virtual ~Kyber_PublicKey() = default;

      std::string algo_name() const override;

      AlgorithmIdentifier algorithm_identifier() const override;

      OID object_identifier() const override;

      size_t key_length() const override;

      size_t estimated_strength() const override;

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

      bool check_key(RandomNumberGenerator&, bool) const override;

      std::unique_ptr<PK_Ops::KEM_Encryption> create_kem_encryption_op(RandomNumberGenerator& rng,

            const std::string& params,

            const std::string& provider) const override;

      KyberMode mode() const;

      void set_binary_encoding(KyberKeyEncoding encoding)

         {

         m_key_encoding = encoding;

         }

      KyberKeyEncoding binary_encoding() const

         {

         return m_key_encoding;

         }

   protected:

      Kyber_PublicKey() {}

Unexecuted instantiation: Botan::Kyber_PublicKey::Kyber_PublicKey()

Unexecuted instantiation: Botan::Kyber_PublicKey::Kyber_PublicKey()

      void initialize_from_encoding(const std::vector<uint8_t>& pub_key,

                                    KyberMode m,

                                    KyberKeyEncoding encoding);

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

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

   protected:

      friend class Kyber_KEM_Encryptor;

      friend class Kyber_KEM_Decryptor;

      std::shared_ptr<Kyber_PublicKeyInternal> m_public;

      KyberKeyEncoding m_key_encoding = KyberKeyEncoding::Full;

   };

class BOTAN_PUBLIC_API(3, 0) Kyber_PrivateKey final : public virtual Kyber_PublicKey, public virtual Private_Key

   {

   public:

      Kyber_PrivateKey(RandomNumberGenerator& rng, KyberMode mode);

      Kyber_PrivateKey(const secure_vector<uint8_t>& sk,

                       KyberMode mode,

                       KyberKeyEncoding encoding);

      Kyber_PrivateKey(const AlgorithmIdentifier& alg_id,

                       const secure_vector<uint8_t>& key_bits);

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

      secure_vector<uint8_t> private_key_bits() const override;

      std::unique_ptr<PK_Ops::KEM_Decryption> create_kem_decryption_op(RandomNumberGenerator& rng,

            const std::string& params,

            const std::string& provider) const override;

   private:

      secure_vector<uint8_t> private_key_bits_raw() const;

      secure_vector<uint8_t> private_key_bits_der() const;

   private:

      friend class Kyber_KEM_Decryptor;

      std::shared_ptr<Kyber_PrivateKeyInternal> m_private;

   };

} // namespace Botan

#endif