// Copyright (c) 2009-2012 The Bitcoin developers
// Copyright (c) 2016-2019 The Spectrecoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "crypter.h"

#include "script.h"
#include "scrypt.h"

#include <string>
#include <vector>
#include <boost/foreach.hpp>
#include <openssl/aes.h>
#include <openssl/evp.h>
#ifdef WIN32
#include <windows.h>
#endif

bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
{
    if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
        return false;

    int i = 0;
    if (nDerivationMethod == 0)
    {
        i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha512(), &chSalt[0],
                          (unsigned char *)&strKeyData[0], strKeyData.size(), nRounds, chKey, chIV);
    }

    if (nDerivationMethod == 1)
    {
        // Passphrase conversion
        uint256 scryptHash = scrypt_salted_multiround_hash((const void*)strKeyData.c_str(), strKeyData.size(), &chSalt[0], 8, nRounds);

        i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha512(), &chSalt[0],
                          (unsigned char *)&scryptHash, sizeof scryptHash, nRounds, chKey, chIV);
        OPENSSL_cleanse(&scryptHash, sizeof scryptHash);
    }


    if (i != (int)WALLET_CRYPTO_KEY_SIZE)
    {
        OPENSSL_cleanse(chKey, sizeof(chKey));
        OPENSSL_cleanse(chIV, sizeof(chIV));
        return false;
    }

    fKeySet = true;
    return true;
}

bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
{
    if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_KEY_SIZE)
        return false;

    memcpy(&chKey[0], &chNewKey[0], sizeof chKey);
    memcpy(&chIV[0], &chNewIV[0], sizeof chIV);

    fKeySet = true;
    return true;
}

bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext)
{
    if (!fKeySet)
        return false;

    // max ciphertext len for a n bytes of plaintext is
    // n + AES_BLOCK_SIZE - 1 bytes
    int nLen = vchPlaintext.size();
    int nCLen = nLen + AES_BLOCK_SIZE, nFLen = 0;
    vchCiphertext = std::vector<unsigned char> (nCLen);

    EVP_CIPHER_CTX *ctx;

    bool fOk = true;

    ctx = EVP_CIPHER_CTX_new();
    if (fOk) fOk = EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
    if (fOk) fOk = EVP_EncryptUpdate(ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen);
    if (fOk) fOk = EVP_EncryptFinal_ex(ctx, (&vchCiphertext[0])+nCLen, &nFLen);
    EVP_CIPHER_CTX_free(ctx);

    if (!fOk) return false;

    vchCiphertext.resize(nCLen + nFLen);
    return true;
}

bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext)
{
    if (!fKeySet)
        return false;

    // plaintext will always be equal to or lesser than length of ciphertext
    int nLen = vchCiphertext.size();
    int nPLen = nLen, nFLen = 0;

    vchPlaintext = CKeyingMaterial(nPLen);

    EVP_CIPHER_CTX *ctx;

    bool fOk = true;

    ctx = EVP_CIPHER_CTX_new();
    if (fOk) fOk = EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
    if (fOk) fOk = EVP_DecryptUpdate(ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen);
    if (fOk) fOk = EVP_DecryptFinal_ex(ctx, (&vchPlaintext[0])+nPLen, &nFLen);
    EVP_CIPHER_CTX_free(ctx);

    if (!fOk) return false;

    vchPlaintext.resize(nPLen + nFLen);
    return true;
}


bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext)
{
    CCrypter cKeyCrypter;
    std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
    if(!cKeyCrypter.SetKey(vMasterKey, chIV))
        return false;
    return cKeyCrypter.Encrypt(*((const CKeyingMaterial*)&vchPlaintext), vchCiphertext);
}

bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& vchPlaintext)
{
    CCrypter cKeyCrypter;
    std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
    memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
    if(!cKeyCrypter.SetKey(vMasterKey, chIV))
        return false;
    return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
}

bool CCryptoKeyStore::SetCrypted()
{
    LOCK(cs_KeyStore);
    if (fUseCrypto)
        return true;
    if (!mapKeys.empty())
        return false;
    fUseCrypto = true;
    return true;
}

bool CCryptoKeyStore::LockKeyStore()
{
    if (!SetCrypted())
        return false;

    {
        LOCK(cs_KeyStore);
        vMasterKey.clear();
    }

    NotifyStatusChanged(this);
    return true;
}

bool CCryptoKeyStore::Unlock(const CKeyingMaterial& vMasterKeyIn)
{
    if (fDebug)
        LogPrintf("CCryptoKeyStore::Unlock()\n");

    {
        LOCK(cs_KeyStore);
        if (!SetCrypted())
            return false;

        int nUnlocked = 0;

        CryptedKeyMap::const_iterator mi = mapCryptedKeys.begin();
        for (; mi != mapCryptedKeys.end(); ++mi)
        {
            const CPubKey &vchPubKey = (*mi).second.first;
            const std::vector<unsigned char> &vchCryptedSecret = (*mi).second.second;
            CSecret vchSecret;

            if (vchCryptedSecret.size() < 1) // key was recieved from stealth/anon txn with wallet locked, will be expanded after this
            {
                if (fDebug)
                    LogPrintf("Skipping unexpanded key %s.\n", vchPubKey.GetHash().ToString().c_str());
                continue;
            };

            if (!DecryptSecret(vMasterKeyIn, vchCryptedSecret, vchPubKey.GetHash(), vchSecret))
            {
                LogPrintf("DecryptSecret() failed.\n");
                return false;
            };

            if (vchSecret.size() != 32)
                return false;

            CKey key;
            key.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());

            if (key.GetPubKey() != vchPubKey)
            {
                LogPrintf("Unlock failed: PubKey mismatch %s.\n", vchPubKey.GetHash().ToString().c_str());
                return false;
            };

            nUnlocked++;
            break;
        };

        if (nUnlocked < 1) // at least 1 key must pass the test
        {
            if (mapCryptedKeys.size() > 0)
            {
                LogPrintf("Unlock failed: No keys unlocked.\n");
                return false;
            };
        };

        vMasterKey = vMasterKeyIn;
    }

    NotifyStatusChanged(this);

    return true;
}

bool CCryptoKeyStore::AddKey(const CKey& key)
{
    return CCryptoKeyStore::AddKeyPubKey(key, key.GetPubKey());
}

bool CCryptoKeyStore::AddKeyPubKey(const CKey& key, const CPubKey &pubkey)
{
    {
        LOCK(cs_KeyStore);
        if (!IsCrypted())
            return CBasicKeyStore::AddKeyPubKey(key, pubkey);
        if (IsLocked())
            return false;
        std::vector<unsigned char> vchCryptedSecret;
        CKeyingMaterial vchSecret(key.begin(), key.end());
        if (!EncryptSecret(vMasterKey, vchSecret, pubkey.GetHash(), vchCryptedSecret))
            return false;

        // -- NOTE: this is CWallet::AddCryptedKey
        if (!AddCryptedKey(pubkey, vchCryptedSecret))
            return false;
    }
    return true;
}


bool CCryptoKeyStore::AddCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret)
{
    {
        LOCK(cs_KeyStore);
        if (!SetCrypted())
            return false;

        mapCryptedKeys[vchPubKey.GetID()] = make_pair(vchPubKey, vchCryptedSecret);
    }
    return true;
}

bool CCryptoKeyStore::GetKey(const CKeyID &address, CKey& keyOut) const
{
    {
        LOCK(cs_KeyStore);
        if (!IsCrypted())
            return CBasicKeyStore::GetKey(address, keyOut);

        CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
        if (mi != mapCryptedKeys.end())
        {
            const CPubKey &vchPubKey = (*mi).second.first;
            const std::vector<unsigned char> &vchCryptedSecret = (*mi).second.second;
            CKeyingMaterial vchSecret;
            if (!DecryptSecret(vMasterKey, vchCryptedSecret, vchPubKey.GetHash(), vchSecret))
                return false;
            if (vchSecret.size() != 32)
                return false;
            keyOut.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());
            return true;
        }
    }
    return false;
}

bool CCryptoKeyStore::GetPubKey(const CKeyID &address, CPubKey& vchPubKeyOut) const
{
    {
        LOCK(cs_KeyStore);
        if (!IsCrypted())
            return CKeyStore::GetPubKey(address, vchPubKeyOut);

        CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
        if (mi != mapCryptedKeys.end())
        {
            vchPubKeyOut = (*mi).second.first;
            return true;
        }
    }
    return false;
}

bool CCryptoKeyStore::EncryptKeys(CKeyingMaterial& vMasterKeyIn)
{
    {
        LOCK(cs_KeyStore);
        if (!mapCryptedKeys.empty() || IsCrypted())
            return false;

        fUseCrypto = true;
        BOOST_FOREACH(KeyMap::value_type& mKey, mapKeys)
        {
            const CKey &key = mKey.second;
            CPubKey vchPubKey = key.GetPubKey();
            CKeyingMaterial vchSecret(key.begin(), key.end());
            std::vector<unsigned char> vchCryptedSecret;
            if (!EncryptSecret(vMasterKeyIn, vchSecret, vchPubKey.GetHash(), vchCryptedSecret))
                return false;
            if (!AddCryptedKey(vchPubKey, vchCryptedSecret))
                return false;
        }
        mapKeys.clear();
    }
    return true;
}
