/*
* Copyright (c) 2013-2021, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*/

#ifndef CRYPTO_KEY_H__
#define CRYPTO_KEY_H__

#include <inttypes.h>
#include "Crypto.h"

namespace i2p {
    namespace crypto {
        class CryptoKeyEncryptor {
        public:

            virtual ~CryptoKeyEncryptor() {};

            virtual void Encrypt(const uint8_t *data, uint8_t *encrypted) = 0;
        };

        class CryptoKeyDecryptor {
        public:

            virtual ~CryptoKeyDecryptor() {};

            virtual bool Decrypt(const uint8_t *encrypted, uint8_t *data) = 0;

            virtual size_t GetPublicKeyLen() const = 0; // we need it to set key in LS2
        };

// ElGamal
        class ElGamalEncryptor : public CryptoKeyEncryptor // for destination
        {
        public:

            ElGamalEncryptor(const uint8_t *pub);

            void Encrypt(const uint8_t *data, uint8_t *encrypted) override; // 222 bytes data, 514 bytes encrypted

        private:

            uint8_t m_PublicKey[256];
        };

        class ElGamalDecryptor : public CryptoKeyDecryptor // for destination
        {
        public:

            ElGamalDecryptor(const uint8_t *priv);

            bool Decrypt(const uint8_t *encrypted, uint8_t *data) override; // 514 bytes encrypted, 222 bytes data
            size_t GetPublicKeyLen() const override { return 256; };

        private:

            uint8_t m_PrivateKey[256];
        };

// ECIES P256

        class ECIESP256Encryptor : public CryptoKeyEncryptor {
        public:

            ECIESP256Encryptor(const uint8_t *pub);

            ~ECIESP256Encryptor();

            void Encrypt(const uint8_t *data, uint8_t *encrypted) override;

        private:

            EC_GROUP *m_Curve;
            EC_POINT *m_PublicKey;
        };


        class ECIESP256Decryptor : public CryptoKeyDecryptor {
        public:

            ECIESP256Decryptor(const uint8_t *priv);

            ~ECIESP256Decryptor();

            bool Decrypt(const uint8_t *encrypted, uint8_t *data) override;

            size_t GetPublicKeyLen() const override { return 64; };

        private:

            EC_GROUP *m_Curve;
            BIGNUM *m_PrivateKey;
        };

        void CreateECIESP256RandomKeys(uint8_t *priv, uint8_t *pub);

// ECIES GOST R 34.10

        class ECIESGOSTR3410Encryptor : public CryptoKeyEncryptor {
        public:

            ECIESGOSTR3410Encryptor(const uint8_t *pub);

            ~ECIESGOSTR3410Encryptor();

            void Encrypt(const uint8_t *data, uint8_t *encrypted) override;

        private:

            EC_POINT *m_PublicKey;
        };


        class ECIESGOSTR3410Decryptor : public CryptoKeyDecryptor {
        public:

            ECIESGOSTR3410Decryptor(const uint8_t *priv);

            ~ECIESGOSTR3410Decryptor();

            bool Decrypt(const uint8_t *encrypted, uint8_t *data) override;

            size_t GetPublicKeyLen() const override { return 64; };

        private:

            BIGNUM *m_PrivateKey;
        };

        void CreateECIESGOSTR3410RandomKeys(uint8_t *priv, uint8_t *pub);

// ECIES-X25519-AEAD-Ratchet

        class ECIESX25519AEADRatchetEncryptor : public CryptoKeyEncryptor {
        public:

            ECIESX25519AEADRatchetEncryptor(const uint8_t *pub);

            ~ECIESX25519AEADRatchetEncryptor() {};

            void Encrypt(const uint8_t *, uint8_t *pub) override;
            // copies m_PublicKey to pub

        private:

            uint8_t m_PublicKey[32];
        };

        class ECIESX25519AEADRatchetDecryptor : public CryptoKeyDecryptor {
        public:

            ECIESX25519AEADRatchetDecryptor(const uint8_t *priv, bool calculatePublic = false);

            ~ECIESX25519AEADRatchetDecryptor() {};

            bool Decrypt(const uint8_t *epub, uint8_t *sharedSecret) override;

            // agree with static and return in sharedSecret (32 bytes)
            size_t GetPublicKeyLen() const override { return 32; };

            const uint8_t *GetPubicKey() const { return m_StaticKeys.GetPublicKey(); };

        private:

            X25519Keys m_StaticKeys;
        };

        void CreateECIESX25519AEADRatchetRandomKeys(uint8_t *priv, uint8_t *pub);
    }
}

#endif