// Copyright (c) 2009-2021 The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_WALLET_CRYPTER_H

#define BITCOIN_WALLET_CRYPTER_H

#include <serialize.h>

#include <support/allocators/secure.h>

#include <script/signingprovider.h>

namespace wallet {

const unsigned int WALLET_CRYPTO_KEY_SIZE = 32;

const unsigned int WALLET_CRYPTO_SALT_SIZE = 8;

const unsigned int WALLET_CRYPTO_IV_SIZE = 16;

/**

 * Private key encryption is done based on a CMasterKey,

 * which holds a salt and random encryption key.

 *

 * CMasterKeys are encrypted using AES-256-CBC using a key

 * derived using derivation method nDerivationMethod

 * (0 == EVP_sha512()) and derivation iterations nDeriveIterations.

 * vchOtherDerivationParameters is provided for alternative algorithms

 * which may require more parameters (such as scrypt).

 *

 * Wallet Private Keys are then encrypted using AES-256-CBC

 * with the double-sha256 of the public key as the IV, and the

 * master key's key as the encryption key (see keystore.[ch]).

 */

/** Master key for wallet encryption */

class CMasterKey

{

public:

    std::vector<unsigned char> vchCryptedKey;

    std::vector<unsigned char> vchSalt;

    //! 0 = EVP_sha512()

    //! 1 = scrypt()

    unsigned int nDerivationMethod;

    unsigned int nDeriveIterations;

    //! Use this for more parameters to key derivation,

    //! such as the various parameters to scrypt

    std::vector<unsigned char> vchOtherDerivationParameters;

    SERIALIZE_METHODS(CMasterKey, obj)

    {

        READWRITE(obj.vchCryptedKey, obj.vchSalt, obj.nDerivationMethod, obj.nDeriveIterations, obj.vchOtherDerivationParameters);

    }

Unexecuted instantiation: _ZN6wallet10CMasterKey16SerializationOpsI10DataStreamKS0_15ActionSerializeEEvRT0_RT_T1_

Unexecuted instantiation: _ZN6wallet10CMasterKey16SerializationOpsI10DataStreamS0_17ActionUnserializeEEvRT0_RT_T1_

    CMasterKey()

    {

        // 25000 rounds is just under 0.1 seconds on a 1.86 GHz Pentium M

        // ie slightly lower than the lowest hardware we need bother supporting

        nDeriveIterations = 25000;

        nDerivationMethod = 0;

        vchOtherDerivationParameters = std::vector<unsigned char>(0);

    }

};

typedef std::vector<unsigned char, secure_allocator<unsigned char> > CKeyingMaterial;

namespace wallet_crypto_tests

{

    class TestCrypter;

}

/** Encryption/decryption context with key information */

class CCrypter

{

friend class wallet_crypto_tests::TestCrypter; // for test access to chKey/chIV

private:

    std::vector<unsigned char, secure_allocator<unsigned char>> vchKey;

    std::vector<unsigned char, secure_allocator<unsigned char>> vchIV;

    bool fKeySet;

    int BytesToKeySHA512AES(std::span<const unsigned char> salt, const SecureString& key_data, int count, unsigned char* key, unsigned char* iv) const;

public:

    bool SetKeyFromPassphrase(const SecureString& key_data, std::span<const unsigned char> salt, const unsigned int rounds, const unsigned int derivation_method);

    bool Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext) const;

    bool Decrypt(std::span<const unsigned char> ciphertext, CKeyingMaterial& plaintext) const;

    bool SetKey(const CKeyingMaterial& new_key, std::span<const unsigned char> new_iv);

    void CleanKey()

    {

        memory_cleanse(vchKey.data(), vchKey.size());

        memory_cleanse(vchIV.data(), vchIV.size());

        fKeySet = false;

    }

    CCrypter()

    {

        fKeySet = false;

        vchKey.resize(WALLET_CRYPTO_KEY_SIZE);

        vchIV.resize(WALLET_CRYPTO_IV_SIZE);

    }

    ~CCrypter()

    {

        CleanKey();

    }

};

bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext);

bool DecryptSecret(const CKeyingMaterial& master_key, std::span<const unsigned char> ciphertext, const uint256& iv, CKeyingMaterial& plaintext);

bool DecryptKey(const CKeyingMaterial& master_key, std::span<const unsigned char> crypted_secret, const CPubKey& pub_key, CKey& key);

} // namespace wallet

#endif // BITCOIN_WALLET_CRYPTER_H