/src/wallet/scriptpubkeyman.cpp

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// Copyright (c) 2019-2021 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <key_io.h>
#include <logging.h>
#include <outputtype.h>
#include <script/descriptor.h>
#include <script/sign.h>
#include <util/bip32.h>
#include <util/strencodings.h>
#include <util/string.h>
#include <util/system.h>
#include <util/time.h>
#include <util/translation.h>
#include <wallet/scriptpubkeyman.h>

#include <optional>

namespace wallet {
//! Value for the first BIP 32 hardened derivation. Can be used as a bit mask and as a value. See BIP 32 for more details.
const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;

bool LegacyScriptPubKeyMan::GetNewDestination(const OutputType type, CTxDestination& dest, bilingual_str& error)
{
    if (LEGACY_OUTPUT_TYPES.count(type) == 0) {
        error = _("Error: Legacy wallets only support the \"legacy\", \"p2sh-segwit\", and \"bech32\" address types");
        return false;
    }
    assert(type != OutputType::BECH32M);

    LOCK(cs_KeyStore);
    error.clear();

    // Generate a new key that is added to wallet
    CPubKey new_key;
    if (!GetKeyFromPool(new_key, type)) {
        error = _("Error: Keypool ran out, please call keypoolrefill first");
        return false;
    }
    LearnRelatedScripts(new_key, type);
    dest = GetDestinationForKey(new_key, type);
    return true;
}

typedef std::vector<unsigned char> valtype;

namespace {

/**
 * This is an enum that tracks the execution context of a script, similar to
 * SigVersion in script/interpreter. It is separate however because we want to
 * distinguish between top-level scriptPubKey execution and P2SH redeemScript
 * execution (a distinction that has no impact on consensus rules).
 */
enum class IsMineSigVersion
{
    TOP = 0,        //!< scriptPubKey execution
    P2SH = 1,       //!< P2SH redeemScript
    WITNESS_V0 = 2, //!< P2WSH witness script execution
};

/**
 * This is an internal representation of isminetype + invalidity.
 * Its order is significant, as we return the max of all explored
 * possibilities.
 */
enum class IsMineResult
{
    NO = 0,         //!< Not ours
    WATCH_ONLY = 1, //!< Included in watch-only balance
    SPENDABLE = 2,  //!< Included in all balances
    INVALID = 3,    //!< Not spendable by anyone (uncompressed pubkey in segwit, P2SH inside P2SH or witness, witness inside witness)
};

bool PermitsUncompressed(IsMineSigVersion sigversion)
{
    return sigversion == IsMineSigVersion::TOP || sigversion == IsMineSigVersion::P2SH;
}

bool HaveKeys(const std::vector<valtype>& pubkeys, const LegacyScriptPubKeyMan& keystore)
{
    for (const valtype& pubkey : pubkeys) {
        CKeyID keyID = CPubKey(pubkey).GetID();
        if (!keystore.HaveKey(keyID)) return false;
    }
    return true;
}

//! Recursively solve script and return spendable/watchonly/invalid status.
//!
//! @param keystore            legacy key and script store
//! @param scriptPubKey        script to solve
//! @param sigversion          script type (top-level / redeemscript / witnessscript)
//! @param recurse_scripthash  whether to recurse into nested p2sh and p2wsh
//!                            scripts or simply treat any script that has been
//!                            stored in the keystore as spendable
IsMineResult IsMineInner(const LegacyScriptPubKeyMan& keystore, const CScript& scriptPubKey, IsMineSigVersion sigversion, bool recurse_scripthash=true)
{
    IsMineResult ret = IsMineResult::NO;

    std::vector<valtype> vSolutions;
    TxoutType whichType = Solver(scriptPubKey, vSolutions);

    CKeyID keyID;
    switch (whichType) {
    case TxoutType::NONSTANDARD:
    case TxoutType::NULL_DATA:
    case TxoutType::WITNESS_UNKNOWN:
    case TxoutType::WITNESS_V1_TAPROOT:
        break;
    case TxoutType::PUBKEY:
        keyID = CPubKey(vSolutions[0]).GetID();
        if (!PermitsUncompressed(sigversion) && vSolutions[0].size() != 33) {
            return IsMineResult::INVALID;
        }
        if (keystore.HaveKey(keyID)) {
            ret = std::max(ret, IsMineResult::SPENDABLE);
        }
        break;
    case TxoutType::WITNESS_V0_KEYHASH:
    {
        if (sigversion == IsMineSigVersion::WITNESS_V0) {
            // P2WPKH inside P2WSH is invalid.
            return IsMineResult::INVALID;
        }
        if (sigversion == IsMineSigVersion::TOP && !keystore.HaveCScript(CScriptID(CScript() << OP_0 << vSolutions[0]))) {
            // We do not support bare witness outputs unless the P2SH version of it would be
            // acceptable as well. This protects against matching before segwit activates.
            // This also applies to the P2WSH case.
            break;
        }
        ret = std::max(ret, IsMineInner(keystore, GetScriptForDestination(PKHash(uint160(vSolutions[0]))), IsMineSigVersion::WITNESS_V0));
        break;
    }
    case TxoutType::PUBKEYHASH:
        keyID = CKeyID(uint160(vSolutions[0]));
        if (!PermitsUncompressed(sigversion)) {
            CPubKey pubkey;
            if (keystore.GetPubKey(keyID, pubkey) && !pubkey.IsCompressed()) {
                return IsMineResult::INVALID;
            }
        }
        if (keystore.HaveKey(keyID)) {
            ret = std::max(ret, IsMineResult::SPENDABLE);
        }
        break;
    case TxoutType::SCRIPTHASH:
    {
        if (sigversion != IsMineSigVersion::TOP) {
            // P2SH inside P2WSH or P2SH is invalid.
            return IsMineResult::INVALID;
        }
        CScriptID scriptID = CScriptID(uint160(vSolutions[0]));
        CScript subscript;
        if (keystore.GetCScript(scriptID, subscript)) {
            ret = std::max(ret, recurse_scripthash ? IsMineInner(keystore, subscript, IsMineSigVersion::P2SH) : IsMineResult::SPENDABLE);
        }
        break;
    }
    case TxoutType::WITNESS_V0_SCRIPTHASH:
    {
        if (sigversion == IsMineSigVersion::WITNESS_V0) {
            // P2WSH inside P2WSH is invalid.
            return IsMineResult::INVALID;
        }
        if (sigversion == IsMineSigVersion::TOP && !keystore.HaveCScript(CScriptID(CScript() << OP_0 << vSolutions[0]))) {
            break;
        }
        uint160 hash;
        CRIPEMD160().Write(vSolutions[0].data(), vSolutions[0].size()).Finalize(hash.begin());
        CScriptID scriptID = CScriptID(hash);
        CScript subscript;
        if (keystore.GetCScript(scriptID, subscript)) {
            ret = std::max(ret, recurse_scripthash ? IsMineInner(keystore, subscript, IsMineSigVersion::WITNESS_V0) : IsMineResult::SPENDABLE);
        }
        break;
    }

    case TxoutType::MULTISIG:
    {
        // Never treat bare multisig outputs as ours (they can still be made watchonly-though)
        if (sigversion == IsMineSigVersion::TOP) {
            break;
        }

        // Only consider transactions "mine" if we own ALL the
        // keys involved. Multi-signature transactions that are
        // partially owned (somebody else has a key that can spend
        // them) enable spend-out-from-under-you attacks, especially
        // in shared-wallet situations.
        std::vector<valtype> keys(vSolutions.begin()+1, vSolutions.begin()+vSolutions.size()-1);
        if (!PermitsUncompressed(sigversion)) {
            for (size_t i = 0; i < keys.size(); i++) {
                if (keys[i].size() != 33) {
                    return IsMineResult::INVALID;
                }
            }
        }
        if (HaveKeys(keys, keystore)) {
            ret = std::max(ret, IsMineResult::SPENDABLE);
        }
        break;
    }
    } // no default case, so the compiler can warn about missing cases

    if (ret == IsMineResult::NO && keystore.HaveWatchOnly(scriptPubKey)) {
        ret = std::max(ret, IsMineResult::WATCH_ONLY);
    }
    return ret;
}

} // namespace

isminetype LegacyScriptPubKeyMan::IsMine(const CScript& script) const
{
    switch (IsMineInner(*this, script, IsMineSigVersion::TOP)) {
    case IsMineResult::INVALID:
    case IsMineResult::NO:
        return ISMINE_NO;
    case IsMineResult::WATCH_ONLY:
        return ISMINE_WATCH_ONLY;
    case IsMineResult::SPENDABLE:
        return ISMINE_SPENDABLE;
    }
    assert(false);
}

bool LegacyScriptPubKeyMan::CheckDecryptionKey(const CKeyingMaterial& master_key, bool accept_no_keys)
{
    {
        LOCK(cs_KeyStore);
        assert(mapKeys.empty());

        bool keyPass = mapCryptedKeys.empty(); // Always pass when there are no encrypted keys
        bool keyFail = false;
        CryptedKeyMap::const_iterator mi = mapCryptedKeys.begin();
        WalletBatch batch(m_storage.GetDatabase());
        for (; mi != mapCryptedKeys.end(); ++mi)
        {
            const CPubKey &vchPubKey = (*mi).second.first;
            const std::vector<unsigned char> &vchCryptedSecret = (*mi).second.second;
            CKey key;
            if (!DecryptKey(master_key, vchCryptedSecret, vchPubKey, key))
            {
                keyFail = true;
                break;
            }
            keyPass = true;
            if (fDecryptionThoroughlyChecked)
                break;
            else {
                // Rewrite these encrypted keys with checksums
                batch.WriteCryptedKey(vchPubKey, vchCryptedSecret, mapKeyMetadata[vchPubKey.GetID()]);
            }
        }
        if (keyPass && keyFail)
        {
            LogPrintf("The wallet is probably corrupted: Some keys decrypt but not all.\n");
            throw std::runtime_error("Error unlocking wallet: some keys decrypt but not all. Your wallet file may be corrupt.");
        }
        if (keyFail || (!keyPass && !accept_no_keys))
            return false;
        fDecryptionThoroughlyChecked = true;
    }
    return true;
}

bool LegacyScriptPubKeyMan::Encrypt(const CKeyingMaterial& master_key, WalletBatch* batch)
{
    LOCK(cs_KeyStore);
    encrypted_batch = batch;
    if (!mapCryptedKeys.empty()) {
        encrypted_batch = nullptr;
        return false;
    }

    KeyMap keys_to_encrypt;
    keys_to_encrypt.swap(mapKeys); // Clear mapKeys so AddCryptedKeyInner will succeed.
    for (const KeyMap::value_type& mKey : keys_to_encrypt)
    {
        const CKey &key = mKey.second;
        CPubKey vchPubKey = key.GetPubKey();
        CKeyingMaterial vchSecret(key.begin(), key.end());
        std::vector<unsigned char> vchCryptedSecret;
        if (!EncryptSecret(master_key, vchSecret, vchPubKey.GetHash(), vchCryptedSecret)) {
            encrypted_batch = nullptr;
            return false;
        }
        if (!AddCryptedKey(vchPubKey, vchCryptedSecret)) {
            encrypted_batch = nullptr;
            return false;
        }
    }
    encrypted_batch = nullptr;
    return true;
}

bool LegacyScriptPubKeyMan::GetReservedDestination(const OutputType type, bool internal, CTxDestination& address, int64_t& index, CKeyPool& keypool, bilingual_str& error)
{
    if (LEGACY_OUTPUT_TYPES.count(type) == 0) {
        error = _("Error: Legacy wallets only support the \"legacy\", \"p2sh-segwit\", and \"bech32\" address types");
        return false;
    }
    assert(type != OutputType::BECH32M);

    LOCK(cs_KeyStore);
    if (!CanGetAddresses(internal)) {
        error = _("Error: Keypool ran out, please call keypoolrefill first");
        return false;
    }

    if (!ReserveKeyFromKeyPool(index, keypool, internal)) {
        error = _("Error: Keypool ran out, please call keypoolrefill first");
        return false;
    }
    address = GetDestinationForKey(keypool.vchPubKey, type);
    return true;
}

bool LegacyScriptPubKeyMan::TopUpInactiveHDChain(const CKeyID seed_id, int64_t index, bool internal)
{
    LOCK(cs_KeyStore);

    if (m_storage.IsLocked()) return false;

    auto it = m_inactive_hd_chains.find(seed_id);
    if (it == m_inactive_hd_chains.end()) {
        return false;
    }

    CHDChain& chain = it->second;

    // Top up key pool
    int64_t target_size = std::max(gArgs.GetIntArg("-keypool", DEFAULT_KEYPOOL_SIZE), (int64_t) 1);

    // "size" of the keypools. Not really the size, actually the difference between index and the chain counter
    // Since chain counter is 1 based and index is 0 based, one of them needs to be offset by 1.
    int64_t kp_size = (internal ? chain.nInternalChainCounter : chain.nExternalChainCounter) - (index + 1);

    // make sure the keypool fits the user-selected target (-keypool)
    int64_t missing = std::max(target_size - kp_size, (int64_t) 0);

    if (missing > 0) {
        WalletBatch batch(m_storage.GetDatabase());
        for (int64_t i = missing; i > 0; --i) {
            GenerateNewKey(batch, chain, internal);
        }
        if (internal) {
            WalletLogPrintf("inactive seed with id %s added %d internal keys\n", HexStr(seed_id), missing);
        } else {
            WalletLogPrintf("inactive seed with id %s added %d keys\n", HexStr(seed_id), missing);
        }
    }
    return true;
}

std::vector<WalletDestination> LegacyScriptPubKeyMan::MarkUnusedAddresses(const CScript& script)
{
    LOCK(cs_KeyStore);
    std::vector<WalletDestination> result;
    // extract addresses and check if they match with an unused keypool key
    for (const auto& keyid : GetAffectedKeys(script, *this)) {
        std::map<CKeyID, int64_t>::const_iterator mi = m_pool_key_to_index.find(keyid);
        if (mi != m_pool_key_to_index.end()) {
            WalletLogPrintf("%s: Detected a used keypool key, mark all keypool keys up to this key as used\n", __func__);
            for (const auto& keypool : MarkReserveKeysAsUsed(mi->second)) {
                // derive all possible destinations as any of them could have been used
                for (const auto& type : LEGACY_OUTPUT_TYPES) {
                    const auto& dest = GetDestinationForKey(keypool.vchPubKey, type);
                    result.push_back({dest, keypool.fInternal});
                }
            }

            if (!TopUp()) {
                WalletLogPrintf("%s: Topping up keypool failed (locked wallet)\n", __func__);
            }
        }

        // Find the key's metadata and check if it's seed id (if it has one) is inactive, i.e. it is not the current m_hd_chain seed id.
        // If so, TopUp the inactive hd chain
        auto it = mapKeyMetadata.find(keyid);
        if (it != mapKeyMetadata.end()){
            CKeyMetadata meta = it->second;
            if (!meta.hd_seed_id.IsNull() && meta.hd_seed_id != m_hd_chain.seed_id) {
                bool internal = (meta.key_origin.path[1] & ~BIP32_HARDENED_KEY_LIMIT) != 0;
                int64_t index = meta.key_origin.path[2] & ~BIP32_HARDENED_KEY_LIMIT;

                if (!TopUpInactiveHDChain(meta.hd_seed_id, index, internal)) {
                    WalletLogPrintf("%s: Adding inactive seed keys failed\n", __func__);
                }
            }
        }
    }

    return result;
}

void LegacyScriptPubKeyMan::UpgradeKeyMetadata()
{
    LOCK(cs_KeyStore);
    if (m_storage.IsLocked() || m_storage.IsWalletFlagSet(WALLET_FLAG_KEY_ORIGIN_METADATA)) {
        return;
    }

    std::unique_ptr<WalletBatch> batch = std::make_unique<WalletBatch>(m_storage.GetDatabase());
    for (auto& meta_pair : mapKeyMetadata) {
        CKeyMetadata& meta = meta_pair.second;
        if (!meta.hd_seed_id.IsNull() && !meta.has_key_origin && meta.hdKeypath != "s") { // If the hdKeypath is "s", that's the seed and it doesn't have a key origin
            CKey key;
            GetKey(meta.hd_seed_id, key);
            CExtKey masterKey;
            masterKey.SetSeed(key);
            // Add to map
            CKeyID master_id = masterKey.key.GetPubKey().GetID();
            std::copy(master_id.begin(), master_id.begin() + 4, meta.key_origin.fingerprint);
            if (!ParseHDKeypath(meta.hdKeypath, meta.key_origin.path)) {
                throw std::runtime_error("Invalid stored hdKeypath");
            }
            meta.has_key_origin = true;
            if (meta.nVersion < CKeyMetadata::VERSION_WITH_KEY_ORIGIN) {
                meta.nVersion = CKeyMetadata::VERSION_WITH_KEY_ORIGIN;
            }

            // Write meta to wallet
            CPubKey pubkey;
            if (GetPubKey(meta_pair.first, pubkey)) {
                batch->WriteKeyMetadata(meta, pubkey, true);
            }
        }
    }
}

bool LegacyScriptPubKeyMan::SetupGeneration(bool force)
{
    if ((CanGenerateKeys() && !force) || m_storage.IsLocked()) {
        return false;
    }

    SetHDSeed(GenerateNewSeed());
    if (!NewKeyPool()) {
        return false;
    }
    return true;
}

bool LegacyScriptPubKeyMan::IsHDEnabled() const
{
    return !m_hd_chain.seed_id.IsNull();
}

bool LegacyScriptPubKeyMan::CanGetAddresses(bool internal) const
{
    LOCK(cs_KeyStore);
    // Check if the keypool has keys
    bool keypool_has_keys;
    if (internal && m_storage.CanSupportFeature(FEATURE_HD_SPLIT)) {
        keypool_has_keys = setInternalKeyPool.size() > 0;
    } else {
        keypool_has_keys = KeypoolCountExternalKeys() > 0;
    }
    // If the keypool doesn't have keys, check if we can generate them
    if (!keypool_has_keys) {
        return CanGenerateKeys();
    }
    return keypool_has_keys;
}

bool LegacyScriptPubKeyMan::Upgrade(int prev_version, int new_version, bilingual_str& error)
{
    LOCK(cs_KeyStore);
    bool hd_upgrade = false;
    bool split_upgrade = false;
    if (IsFeatureSupported(new_version, FEATURE_HD) && !IsHDEnabled()) {
        WalletLogPrintf("Upgrading wallet to HD\n");
        m_storage.SetMinVersion(FEATURE_HD);

        // generate a new master key
        CPubKey masterPubKey = GenerateNewSeed();
        SetHDSeed(masterPubKey);
        hd_upgrade = true;
    }
    // Upgrade to HD chain split if necessary
    if (!IsFeatureSupported(prev_version, FEATURE_HD_SPLIT) && IsFeatureSupported(new_version, FEATURE_HD_SPLIT)) {
        WalletLogPrintf("Upgrading wallet to use HD chain split\n");
        m_storage.SetMinVersion(FEATURE_PRE_SPLIT_KEYPOOL);
        split_upgrade = FEATURE_HD_SPLIT > prev_version;
        // Upgrade the HDChain
        if (m_hd_chain.nVersion < CHDChain::VERSION_HD_CHAIN_SPLIT) {
            m_hd_chain.nVersion = CHDChain::VERSION_HD_CHAIN_SPLIT;
            if (!WalletBatch(m_storage.GetDatabase()).WriteHDChain(m_hd_chain)) {
                throw std::runtime_error(std::string(__func__) + ": writing chain failed");
            }
        }
    }
    // Mark all keys currently in the keypool as pre-split
    if (split_upgrade) {
        MarkPreSplitKeys();
    }
    // Regenerate the keypool if upgraded to HD
    if (hd_upgrade) {
        if (!NewKeyPool()) {
            error = _("Unable to generate keys");
            return false;
        }
    }
    return true;
}

bool LegacyScriptPubKeyMan::HavePrivateKeys() const
{
    LOCK(cs_KeyStore);
    return !mapKeys.empty() || !mapCryptedKeys.empty();
}

void LegacyScriptPubKeyMan::RewriteDB()
{
    LOCK(cs_KeyStore);
    setInternalKeyPool.clear();
    setExternalKeyPool.clear();
    m_pool_key_to_index.clear();
    // Note: can't top-up keypool here, because wallet is locked.
    // User will be prompted to unlock wallet the next operation
    // that requires a new key.
}

static int64_t GetOldestKeyTimeInPool(const std::set<int64_t>& setKeyPool, WalletBatch& batch) {
    if (setKeyPool.empty()) {
        return GetTime();
    }

    CKeyPool keypool;
    int64_t nIndex = *(setKeyPool.begin());
    if (!batch.ReadPool(nIndex, keypool)) {
        throw std::runtime_error(std::string(__func__) + ": read oldest key in keypool failed");
    }
    assert(keypool.vchPubKey.IsValid());
    return keypool.nTime;
}

std::optional<int64_t> LegacyScriptPubKeyMan::GetOldestKeyPoolTime() const
{
    LOCK(cs_KeyStore);

    WalletBatch batch(m_storage.GetDatabase());

    // load oldest key from keypool, get time and return
    int64_t oldestKey = GetOldestKeyTimeInPool(setExternalKeyPool, batch);
    if (IsHDEnabled() && m_storage.CanSupportFeature(FEATURE_HD_SPLIT)) {
        oldestKey = std::max(GetOldestKeyTimeInPool(setInternalKeyPool, batch), oldestKey);
        if (!set_pre_split_keypool.empty()) {
            oldestKey = std::max(GetOldestKeyTimeInPool(set_pre_split_keypool, batch), oldestKey);
        }
    }

    return oldestKey;
}

size_t LegacyScriptPubKeyMan::KeypoolCountExternalKeys() const
{
    LOCK(cs_KeyStore);
    return setExternalKeyPool.size() + set_pre_split_keypool.size();
}

unsigned int LegacyScriptPubKeyMan::GetKeyPoolSize() const
{
    LOCK(cs_KeyStore);
    return setInternalKeyPool.size() + setExternalKeyPool.size() + set_pre_split_keypool.size();
}

int64_t LegacyScriptPubKeyMan::GetTimeFirstKey() const
{
    LOCK(cs_KeyStore);
    return nTimeFirstKey;
}

std::unique_ptr<SigningProvider> LegacyScriptPubKeyMan::GetSolvingProvider(const CScript& script) const
{
    return std::make_unique<LegacySigningProvider>(*this);
}

bool LegacyScriptPubKeyMan::CanProvide(const CScript& script, SignatureData& sigdata)
{
    IsMineResult ismine = IsMineInner(*this, script, IsMineSigVersion::TOP, /* recurse_scripthash= */ false);
    if (ismine == IsMineResult::SPENDABLE || ismine == IsMineResult::WATCH_ONLY) {
        // If ismine, it means we recognize keys or script ids in the script, or
        // are watching the script itself, and we can at least provide metadata
        // or solving information, even if not able to sign fully.
        return true;
    } else {
        // If, given the stuff in sigdata, we could make a valid sigature, then we can provide for this script
        ProduceSignature(*this, DUMMY_SIGNATURE_CREATOR, script, sigdata);
        if (!sigdata.signatures.empty()) {
            // If we could make signatures, make sure we have a private key to actually make a signature
            bool has_privkeys = false;
            for (const auto& key_sig_pair : sigdata.signatures) {
                has_privkeys |= HaveKey(key_sig_pair.first);
            }
            return has_privkeys;
        }
        return false;
    }
}

bool LegacyScriptPubKeyMan::SignTransaction(CMutableTransaction& tx, const std::map<COutPoint, Coin>& coins, int sighash, std::map<int, bilingual_str>& input_errors) const
{
    return ::SignTransaction(tx, this, coins, sighash, input_errors);
}

SigningResult LegacyScriptPubKeyMan::SignMessage(const std::string& message, const PKHash& pkhash, std::string& str_sig) const
{
    CKey key;
    if (!GetKey(ToKeyID(pkhash), key)) {
        return SigningResult::PRIVATE_KEY_NOT_AVAILABLE;
    }

    if (MessageSign(key, message, str_sig)) {
        return SigningResult::OK;
    }
    return SigningResult::SIGNING_FAILED;
}

TransactionError LegacyScriptPubKeyMan::FillPSBT(PartiallySignedTransaction& psbtx, const PrecomputedTransactionData& txdata, int sighash_type, bool sign, bool bip32derivs, int* n_signed, bool finalize) const
{
    if (n_signed) {
        *n_signed = 0;
    }
    for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
        const CTxIn& txin = psbtx.tx->vin[i];
        PSBTInput& input = psbtx.inputs.at(i);

        if (PSBTInputSigned(input)) {
            continue;
        }

        // Get the Sighash type
        if (sign && input.sighash_type != std::nullopt && *input.sighash_type != sighash_type) {
            return TransactionError::SIGHASH_MISMATCH;
        }

        // Check non_witness_utxo has specified prevout
        if (input.non_witness_utxo) {
            if (txin.prevout.n >= input.non_witness_utxo->vout.size()) {
                return TransactionError::MISSING_INPUTS;
            }
        } else if (input.witness_utxo.IsNull()) {
            // There's no UTXO so we can just skip this now
            continue;
        }
        SignatureData sigdata;
        input.FillSignatureData(sigdata);
        SignPSBTInput(HidingSigningProvider(this, !sign, !bip32derivs), psbtx, i, &txdata, sighash_type, nullptr, finalize);

        bool signed_one = PSBTInputSigned(input);
        if (n_signed && (signed_one || !sign)) {
            // If sign is false, we assume that we _could_ sign if we get here. This
            // will never have false negatives; it is hard to tell under what i
            // circumstances it could have false positives.
            (*n_signed)++;
        }
    }

    // Fill in the bip32 keypaths and redeemscripts for the outputs so that hardware wallets can identify change
    for (unsigned int i = 0; i < psbtx.tx->vout.size(); ++i) {
        UpdatePSBTOutput(HidingSigningProvider(this, true, !bip32derivs), psbtx, i);
    }

    return TransactionError::OK;
}

std::unique_ptr<CKeyMetadata> LegacyScriptPubKeyMan::GetMetadata(const CTxDestination& dest) const
{
    LOCK(cs_KeyStore);

    CKeyID key_id = GetKeyForDestination(*this, dest);
    if (!key_id.IsNull()) {
        auto it = mapKeyMetadata.find(key_id);
        if (it != mapKeyMetadata.end()) {
            return std::make_unique<CKeyMetadata>(it->second);
        }
    }

    CScript scriptPubKey = GetScriptForDestination(dest);
    auto it = m_script_metadata.find(CScriptID(scriptPubKey));
    if (it != m_script_metadata.end()) {
        return std::make_unique<CKeyMetadata>(it->second);
    }

    return nullptr;
}

uint256 LegacyScriptPubKeyMan::GetID() const
{
    return uint256::ONE;
}

/**
 * Update wallet first key creation time. This should be called whenever keys
 * are added to the wallet, with the oldest key creation time.
 */
void LegacyScriptPubKeyMan::UpdateTimeFirstKey(int64_t nCreateTime)
{
    AssertLockHeld(cs_KeyStore);
    if (nCreateTime <= 1) {
        // Cannot determine birthday information, so set the wallet birthday to
        // the beginning of time.
        nTimeFirstKey = 1;
    } else if (!nTimeFirstKey || nCreateTime < nTimeFirstKey) {
        nTimeFirstKey = nCreateTime;
    }
}

bool LegacyScriptPubKeyMan::LoadKey(const CKey& key, const CPubKey &pubkey)
{
    return AddKeyPubKeyInner(key, pubkey);
}

bool LegacyScriptPubKeyMan::AddKeyPubKey(const CKey& secret, const CPubKey &pubkey)
{
    LOCK(cs_KeyStore);
    WalletBatch batch(m_storage.GetDatabase());
    return LegacyScriptPubKeyMan::AddKeyPubKeyWithDB(batch, secret, pubkey);
}

bool LegacyScriptPubKeyMan::AddKeyPubKeyWithDB(WalletBatch& batch, const CKey& secret, const CPubKey& pubkey)
{
    AssertLockHeld(cs_KeyStore);

    // Make sure we aren't adding private keys to private key disabled wallets
    assert(!m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS));

    // FillableSigningProvider has no concept of wallet databases, but calls AddCryptedKey
    // which is overridden below.  To avoid flushes, the database handle is
    // tunneled through to it.
    bool needsDB = !encrypted_batch;
    if (needsDB) {
        encrypted_batch = &batch;
    }
    if (!AddKeyPubKeyInner(secret, pubkey)) {
        if (needsDB) encrypted_batch = nullptr;
        return false;
    }
    if (needsDB) encrypted_batch = nullptr;

    // check if we need to remove from watch-only
    CScript script;
    script = GetScriptForDestination(PKHash(pubkey));
    if (HaveWatchOnly(script)) {
        RemoveWatchOnly(script);
    }
    script = GetScriptForRawPubKey(pubkey);
    if (HaveWatchOnly(script)) {
        RemoveWatchOnly(script);
    }

    if (!m_storage.HasEncryptionKeys()) {
        return batch.WriteKey(pubkey,
                                                 secret.GetPrivKey(),
                                                 mapKeyMetadata[pubkey.GetID()]);
    }
    m_storage.UnsetBlankWalletFlag(batch);
    return true;
}

bool LegacyScriptPubKeyMan::LoadCScript(const CScript& redeemScript)
{
    /* A sanity check was added in pull #3843 to avoid adding redeemScripts
     * that never can be redeemed. However, old wallets may still contain
     * these. Do not add them to the wallet and warn. */
    if (redeemScript.size() > MAX_SCRIPT_ELEMENT_SIZE)
    {
        std::string strAddr = EncodeDestination(ScriptHash(redeemScript));
        WalletLogPrintf("%s: Warning: This wallet contains a redeemScript of size %i which exceeds maximum size %i thus can never be redeemed. Do not use address %s.\n", __func__, redeemScript.size(), MAX_SCRIPT_ELEMENT_SIZE, strAddr);
        return true;
    }

    return FillableSigningProvider::AddCScript(redeemScript);
}

void LegacyScriptPubKeyMan::LoadKeyMetadata(const CKeyID& keyID, const CKeyMetadata& meta)
{
    LOCK(cs_KeyStore);
    UpdateTimeFirstKey(meta.nCreateTime);
    mapKeyMetadata[keyID] = meta;
}

void LegacyScriptPubKeyMan::LoadScriptMetadata(const CScriptID& script_id, const CKeyMetadata& meta)
{
    LOCK(cs_KeyStore);
    UpdateTimeFirstKey(meta.nCreateTime);
    m_script_metadata[script_id] = meta;
}

bool LegacyScriptPubKeyMan::AddKeyPubKeyInner(const CKey& key, const CPubKey &pubkey)
{
    LOCK(cs_KeyStore);
    if (!m_storage.HasEncryptionKeys()) {
        return FillableSigningProvider::AddKeyPubKey(key, pubkey);
    }

    if (m_storage.IsLocked()) {
        return false;
    }

    std::vector<unsigned char> vchCryptedSecret;
    CKeyingMaterial vchSecret(key.begin(), key.end());
    if (!EncryptSecret(m_storage.GetEncryptionKey(), vchSecret, pubkey.GetHash(), vchCryptedSecret)) {
        return false;
    }

    if (!AddCryptedKey(pubkey, vchCryptedSecret)) {
        return false;
    }
    return true;
}

bool LegacyScriptPubKeyMan::LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret, bool checksum_valid)
{
    // Set fDecryptionThoroughlyChecked to false when the checksum is invalid
    if (!checksum_valid) {
        fDecryptionThoroughlyChecked = false;
    }

    return AddCryptedKeyInner(vchPubKey, vchCryptedSecret);
}

bool LegacyScriptPubKeyMan::AddCryptedKeyInner(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret)
{
    LOCK(cs_KeyStore);
    assert(mapKeys.empty());

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

bool LegacyScriptPubKeyMan::AddCryptedKey(const CPubKey &vchPubKey,
                            const std::vector<unsigned char> &vchCryptedSecret)
{
    if (!AddCryptedKeyInner(vchPubKey, vchCryptedSecret))
        return false;
    {
        LOCK(cs_KeyStore);
        if (encrypted_batch)
            return encrypted_batch->WriteCryptedKey(vchPubKey,
                                                        vchCryptedSecret,
                                                        mapKeyMetadata[vchPubKey.GetID()]);
        else
            return WalletBatch(m_storage.GetDatabase()).WriteCryptedKey(vchPubKey,
                                                            vchCryptedSecret,
                                                            mapKeyMetadata[vchPubKey.GetID()]);
    }
}

bool LegacyScriptPubKeyMan::HaveWatchOnly(const CScript &dest) const
{
    LOCK(cs_KeyStore);
    return setWatchOnly.count(dest) > 0;
}

bool LegacyScriptPubKeyMan::HaveWatchOnly() const
{
    LOCK(cs_KeyStore);
    return (!setWatchOnly.empty());
}

static bool ExtractPubKey(const CScript &dest, CPubKey& pubKeyOut)
{
    std::vector<std::vector<unsigned char>> solutions;
    return Solver(dest, solutions) == TxoutType::PUBKEY &&
        (pubKeyOut = CPubKey(solutions[0])).IsFullyValid();
}

bool LegacyScriptPubKeyMan::RemoveWatchOnly(const CScript &dest)
{
    {
        LOCK(cs_KeyStore);
        setWatchOnly.erase(dest);
        CPubKey pubKey;
        if (ExtractPubKey(dest, pubKey)) {
            mapWatchKeys.erase(pubKey.GetID());
        }
        // Related CScripts are not removed; having superfluous scripts around is
        // harmless (see comment in ImplicitlyLearnRelatedKeyScripts).
    }

    if (!HaveWatchOnly())
        NotifyWatchonlyChanged(false);
    if (!WalletBatch(m_storage.GetDatabase()).EraseWatchOnly(dest))
        return false;

    return true;
}

bool LegacyScriptPubKeyMan::LoadWatchOnly(const CScript &dest)
{
    return AddWatchOnlyInMem(dest);
}

bool LegacyScriptPubKeyMan::AddWatchOnlyInMem(const CScript &dest)
{
    LOCK(cs_KeyStore);
    setWatchOnly.insert(dest);
    CPubKey pubKey;
    if (ExtractPubKey(dest, pubKey)) {
        mapWatchKeys[pubKey.GetID()] = pubKey;
        ImplicitlyLearnRelatedKeyScripts(pubKey);
    }
    return true;
}

bool LegacyScriptPubKeyMan::AddWatchOnlyWithDB(WalletBatch &batch, const CScript& dest)
{
    if (!AddWatchOnlyInMem(dest))
        return false;
    const CKeyMetadata& meta = m_script_metadata[CScriptID(dest)];
    UpdateTimeFirstKey(meta.nCreateTime);
    NotifyWatchonlyChanged(true);
    if (batch.WriteWatchOnly(dest, meta)) {
        m_storage.UnsetBlankWalletFlag(batch);
        return true;
    }
    return false;
}

bool LegacyScriptPubKeyMan::AddWatchOnlyWithDB(WalletBatch &batch, const CScript& dest, int64_t create_time)
{
    m_script_metadata[CScriptID(dest)].nCreateTime = create_time;
    return AddWatchOnlyWithDB(batch, dest);
}

bool LegacyScriptPubKeyMan::AddWatchOnly(const CScript& dest)
{
    WalletBatch batch(m_storage.GetDatabase());
    return AddWatchOnlyWithDB(batch, dest);
}

bool LegacyScriptPubKeyMan::AddWatchOnly(const CScript& dest, int64_t nCreateTime)
{
    m_script_metadata[CScriptID(dest)].nCreateTime = nCreateTime;
    return AddWatchOnly(dest);
}

void LegacyScriptPubKeyMan::LoadHDChain(const CHDChain& chain)
{
    LOCK(cs_KeyStore);
    m_hd_chain = chain;
}

void LegacyScriptPubKeyMan::AddHDChain(const CHDChain& chain)
{
    LOCK(cs_KeyStore);
    // Store the new chain
    if (!WalletBatch(m_storage.GetDatabase()).WriteHDChain(chain)) {
        throw std::runtime_error(std::string(__func__) + ": writing chain failed");
    }
    // When there's an old chain, add it as an inactive chain as we are now rotating hd chains
    if (!m_hd_chain.seed_id.IsNull()) {
        AddInactiveHDChain(m_hd_chain);
    }

    m_hd_chain = chain;
}

void LegacyScriptPubKeyMan::AddInactiveHDChain(const CHDChain& chain)
{
    LOCK(cs_KeyStore);
    assert(!chain.seed_id.IsNull());
    m_inactive_hd_chains[chain.seed_id] = chain;
}

bool LegacyScriptPubKeyMan::HaveKey(const CKeyID &address) const
{
    LOCK(cs_KeyStore);
    if (!m_storage.HasEncryptionKeys()) {
        return FillableSigningProvider::HaveKey(address);
    }
    return mapCryptedKeys.count(address) > 0;
}

bool LegacyScriptPubKeyMan::GetKey(const CKeyID &address, CKey& keyOut) const
{
    LOCK(cs_KeyStore);
    if (!m_storage.HasEncryptionKeys()) {
        return FillableSigningProvider::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;
        return DecryptKey(m_storage.GetEncryptionKey(), vchCryptedSecret, vchPubKey, keyOut);
    }
    return false;
}

bool LegacyScriptPubKeyMan::GetKeyOrigin(const CKeyID& keyID, KeyOriginInfo& info) const
{
    CKeyMetadata meta;
    {
        LOCK(cs_KeyStore);
        auto it = mapKeyMetadata.find(keyID);
        if (it != mapKeyMetadata.end()) {
            meta = it->second;
        }
    }
    if (meta.has_key_origin) {
        std::copy(meta.key_origin.fingerprint, meta.key_origin.fingerprint + 4, info.fingerprint);
        info.path = meta.key_origin.path;
    } else { // Single pubkeys get the master fingerprint of themselves
        std::copy(keyID.begin(), keyID.begin() + 4, info.fingerprint);
    }
    return true;
}

bool LegacyScriptPubKeyMan::GetWatchPubKey(const CKeyID &address, CPubKey &pubkey_out) const
{
    LOCK(cs_KeyStore);
    WatchKeyMap::const_iterator it = mapWatchKeys.find(address);
    if (it != mapWatchKeys.end()) {
        pubkey_out = it->second;
        return true;
    }
    return false;
}

bool LegacyScriptPubKeyMan::GetPubKey(const CKeyID &address, CPubKey& vchPubKeyOut) const
{
    LOCK(cs_KeyStore);
    if (!m_storage.HasEncryptionKeys()) {
        if (!FillableSigningProvider::GetPubKey(address, vchPubKeyOut)) {
            return GetWatchPubKey(address, vchPubKeyOut);
        }
        return true;
    }

    CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
    if (mi != mapCryptedKeys.end())
    {
        vchPubKeyOut = (*mi).second.first;
        return true;
    }
    // Check for watch-only pubkeys
    return GetWatchPubKey(address, vchPubKeyOut);
}

CPubKey LegacyScriptPubKeyMan::GenerateNewKey(WalletBatch &batch, CHDChain& hd_chain, bool internal)
{
    assert(!m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS));
    assert(!m_storage.IsWalletFlagSet(WALLET_FLAG_BLANK_WALLET));
    AssertLockHeld(cs_KeyStore);
    bool fCompressed = m_storage.CanSupportFeature(FEATURE_COMPRPUBKEY); // default to compressed public keys if we want 0.6.0 wallets

    CKey secret;

    // Create new metadata
    int64_t nCreationTime = GetTime();
    CKeyMetadata metadata(nCreationTime);

    // use HD key derivation if HD was enabled during wallet creation and a seed is present
    if (IsHDEnabled()) {
        DeriveNewChildKey(batch, metadata, secret, hd_chain, (m_storage.CanSupportFeature(FEATURE_HD_SPLIT) ? internal : false));
    } else {
        secret.MakeNewKey(fCompressed);
    }

    // Compressed public keys were introduced in version 0.6.0
    if (fCompressed) {
        m_storage.SetMinVersion(FEATURE_COMPRPUBKEY);
    }

    CPubKey pubkey = secret.GetPubKey();
    assert(secret.VerifyPubKey(pubkey));

    mapKeyMetadata[pubkey.GetID()] = metadata;
    UpdateTimeFirstKey(nCreationTime);

    if (!AddKeyPubKeyWithDB(batch, secret, pubkey)) {
        throw std::runtime_error(std::string(__func__) + ": AddKey failed");
    }
    return pubkey;
}

void LegacyScriptPubKeyMan::DeriveNewChildKey(WalletBatch &batch, CKeyMetadata& metadata, CKey& secret, CHDChain& hd_chain, bool internal)
{
    // for now we use a fixed keypath scheme of m/0'/0'/k
    CKey seed;                     //seed (256bit)
    CExtKey masterKey;             //hd master key
    CExtKey accountKey;            //key at m/0'
    CExtKey chainChildKey;         //key at m/0'/0' (external) or m/0'/1' (internal)
    CExtKey childKey;              //key at m/0'/0'/<n>'

    // try to get the seed
    if (!GetKey(hd_chain.seed_id, seed))
        throw std::runtime_error(std::string(__func__) + ": seed not found");

    masterKey.SetSeed(seed);

    // derive m/0'
    // use hardened derivation (child keys >= 0x80000000 are hardened after bip32)
    masterKey.Derive(accountKey, BIP32_HARDENED_KEY_LIMIT);

    // derive m/0'/0' (external chain) OR m/0'/1' (internal chain)
    assert(internal ? m_storage.CanSupportFeature(FEATURE_HD_SPLIT) : true);
    accountKey.Derive(chainChildKey, BIP32_HARDENED_KEY_LIMIT+(internal ? 1 : 0));

    // derive child key at next index, skip keys already known to the wallet
    do {
        // always derive hardened keys
        // childIndex | BIP32_HARDENED_KEY_LIMIT = derive childIndex in hardened child-index-range
        // example: 1 | BIP32_HARDENED_KEY_LIMIT == 0x80000001 == 2147483649
        if (internal) {
            chainChildKey.Derive(childKey, hd_chain.nInternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            metadata.hdKeypath = "m/0'/1'/" + ToString(hd_chain.nInternalChainCounter) + "'";
            metadata.key_origin.path.push_back(0 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(1 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(hd_chain.nInternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            hd_chain.nInternalChainCounter++;
        }
        else {
            chainChildKey.Derive(childKey, hd_chain.nExternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            metadata.hdKeypath = "m/0'/0'/" + ToString(hd_chain.nExternalChainCounter) + "'";
            metadata.key_origin.path.push_back(0 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(0 | BIP32_HARDENED_KEY_LIMIT);
            metadata.key_origin.path.push_back(hd_chain.nExternalChainCounter | BIP32_HARDENED_KEY_LIMIT);
            hd_chain.nExternalChainCounter++;
        }
    } while (HaveKey(childKey.key.GetPubKey().GetID()));
    secret = childKey.key;
    metadata.hd_seed_id = hd_chain.seed_id;
    CKeyID master_id = masterKey.key.GetPubKey().GetID();
    std::copy(master_id.begin(), master_id.begin() + 4, metadata.key_origin.fingerprint);
    metadata.has_key_origin = true;
    // update the chain model in the database
    if (hd_chain.seed_id == m_hd_chain.seed_id && !batch.WriteHDChain(hd_chain))
        throw std::runtime_error(std::string(__func__) + ": writing HD chain model failed");
}

void LegacyScriptPubKeyMan::LoadKeyPool(int64_t nIndex, const CKeyPool &keypool)
{
    LOCK(cs_KeyStore);
    if (keypool.m_pre_split) {
        set_pre_split_keypool.insert(nIndex);
    } else if (keypool.fInternal) {
        setInternalKeyPool.insert(nIndex);
    } else {
        setExternalKeyPool.insert(nIndex);
    }
    m_max_keypool_index = std::max(m_max_keypool_index, nIndex);
    m_pool_key_to_index[keypool.vchPubKey.GetID()] = nIndex;

    // If no metadata exists yet, create a default with the pool key's
    // creation time. Note that this may be overwritten by actually
    // stored metadata for that key later, which is fine.
    CKeyID keyid = keypool.vchPubKey.GetID();
    if (mapKeyMetadata.count(keyid) == 0)
        mapKeyMetadata[keyid] = CKeyMetadata(keypool.nTime);
}

bool LegacyScriptPubKeyMan::CanGenerateKeys() const
{
    // A wallet can generate keys if it has an HD seed (IsHDEnabled) or it is a non-HD wallet (pre FEATURE_HD)
    LOCK(cs_KeyStore);
    return IsHDEnabled() || !m_storage.CanSupportFeature(FEATURE_HD);
}

CPubKey LegacyScriptPubKeyMan::GenerateNewSeed()
{
    assert(!m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS));
    CKey key;
    key.MakeNewKey(true);
    return DeriveNewSeed(key);
}

CPubKey LegacyScriptPubKeyMan::DeriveNewSeed(const CKey& key)
{
    int64_t nCreationTime = GetTime();
    CKeyMetadata metadata(nCreationTime);

    // calculate the seed
    CPubKey seed = key.GetPubKey();
    assert(key.VerifyPubKey(seed));

    // set the hd keypath to "s" -> Seed, refers the seed to itself
    metadata.hdKeypath     = "s";
    metadata.has_key_origin = false;
    metadata.hd_seed_id = seed.GetID();

    {
        LOCK(cs_KeyStore);

        // mem store the metadata
        mapKeyMetadata[seed.GetID()] = metadata;

        // write the key&metadata to the database
        if (!AddKeyPubKey(key, seed))
            throw std::runtime_error(std::string(__func__) + ": AddKeyPubKey failed");
    }

    return seed;
}

void LegacyScriptPubKeyMan::SetHDSeed(const CPubKey& seed)
{
    LOCK(cs_KeyStore);
    // store the keyid (hash160) together with
    // the child index counter in the database
    // as a hdchain object
    CHDChain newHdChain;
    newHdChain.nVersion = m_storage.CanSupportFeature(FEATURE_HD_SPLIT) ? CHDChain::VERSION_HD_CHAIN_SPLIT : CHDChain::VERSION_HD_BASE;
    newHdChain.seed_id = seed.GetID();
    AddHDChain(newHdChain);
    NotifyCanGetAddressesChanged();
    WalletBatch batch(m_storage.GetDatabase());
    m_storage.UnsetBlankWalletFlag(batch);
}

/**
 * Mark old keypool keys as used,
 * and generate all new keys
 */
bool LegacyScriptPubKeyMan::NewKeyPool()
{
    if (m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
        return false;
    }
    {
        LOCK(cs_KeyStore);
        WalletBatch batch(m_storage.GetDatabase());

        for (const int64_t nIndex : setInternalKeyPool) {
            batch.ErasePool(nIndex);
        }
        setInternalKeyPool.clear();

        for (const int64_t nIndex : setExternalKeyPool) {
            batch.ErasePool(nIndex);
        }
        setExternalKeyPool.clear();

        for (const int64_t nIndex : set_pre_split_keypool) {
            batch.ErasePool(nIndex);
        }
        set_pre_split_keypool.clear();

        m_pool_key_to_index.clear();

        if (!TopUp()) {
            return false;
        }
        WalletLogPrintf("LegacyScriptPubKeyMan::NewKeyPool rewrote keypool\n");
    }
    return true;
}

bool LegacyScriptPubKeyMan::TopUp(unsigned int kpSize)
{
    if (!CanGenerateKeys()) {
        return false;
    }
    {
        LOCK(cs_KeyStore);

        if (m_storage.IsLocked()) return false;

        // Top up key pool
        unsigned int nTargetSize;
        if (kpSize > 0)
            nTargetSize = kpSize;
        else
            nTargetSize = std::max(gArgs.GetIntArg("-keypool", DEFAULT_KEYPOOL_SIZE), (int64_t) 0);

        // count amount of available keys (internal, external)
        // make sure the keypool of external and internal keys fits the user selected target (-keypool)
        int64_t missingExternal = std::max(std::max((int64_t) nTargetSize, (int64_t) 1) - (int64_t)setExternalKeyPool.size(), (int64_t) 0);
        int64_t missingInternal = std::max(std::max((int64_t) nTargetSize, (int64_t) 1) - (int64_t)setInternalKeyPool.size(), (int64_t) 0);

        if (!IsHDEnabled() || !m_storage.CanSupportFeature(FEATURE_HD_SPLIT))
        {
            // don't create extra internal keys
            missingInternal = 0;
        }
        bool internal = false;
        WalletBatch batch(m_storage.GetDatabase());
        for (int64_t i = missingInternal + missingExternal; i--;)
        {
            if (i < missingInternal) {
                internal = true;
            }

            CPubKey pubkey(GenerateNewKey(batch, m_hd_chain, internal));
            AddKeypoolPubkeyWithDB(pubkey, internal, batch);
        }
        if (missingInternal + missingExternal > 0) {
            WalletLogPrintf("keypool added %d keys (%d internal), size=%u (%u internal)\n", missingInternal + missingExternal, missingInternal, setInternalKeyPool.size() + setExternalKeyPool.size() + set_pre_split_keypool.size(), setInternalKeyPool.size());
        }
    }
    NotifyCanGetAddressesChanged();
    return true;
}

void LegacyScriptPubKeyMan::AddKeypoolPubkeyWithDB(const CPubKey& pubkey, const bool internal, WalletBatch& batch)
{
    LOCK(cs_KeyStore);
    assert(m_max_keypool_index < std::numeric_limits<int64_t>::max()); // How in the hell did you use so many keys?
    int64_t index = ++m_max_keypool_index;
    if (!batch.WritePool(index, CKeyPool(pubkey, internal))) {
        throw std::runtime_error(std::string(__func__) + ": writing imported pubkey failed");
    }
    if (internal) {
        setInternalKeyPool.insert(index);
    } else {
        setExternalKeyPool.insert(index);
    }
    m_pool_key_to_index[pubkey.GetID()] = index;
}

void LegacyScriptPubKeyMan::KeepDestination(int64_t nIndex, const OutputType& type)
{
    assert(type != OutputType::BECH32M);
    // Remove from key pool
    WalletBatch batch(m_storage.GetDatabase());
    batch.ErasePool(nIndex);
    CPubKey pubkey;
    bool have_pk = GetPubKey(m_index_to_reserved_key.at(nIndex), pubkey);
    assert(have_pk);
    LearnRelatedScripts(pubkey, type);
    m_index_to_reserved_key.erase(nIndex);
    WalletLogPrintf("keypool keep %d\n", nIndex);
}

void LegacyScriptPubKeyMan::ReturnDestination(int64_t nIndex, bool fInternal, const CTxDestination&)
{
    // Return to key pool
    {
        LOCK(cs_KeyStore);
        if (fInternal) {
            setInternalKeyPool.insert(nIndex);
        } else if (!set_pre_split_keypool.empty()) {
            set_pre_split_keypool.insert(nIndex);
        } else {
            setExternalKeyPool.insert(nIndex);
        }
        CKeyID& pubkey_id = m_index_to_reserved_key.at(nIndex);
        m_pool_key_to_index[pubkey_id] = nIndex;
        m_index_to_reserved_key.erase(nIndex);
        NotifyCanGetAddressesChanged();
    }
    WalletLogPrintf("keypool return %d\n", nIndex);
}

bool LegacyScriptPubKeyMan::GetKeyFromPool(CPubKey& result, const OutputType type, bool internal)
{
    assert(type != OutputType::BECH32M);
    if (!CanGetAddresses(internal)) {
        return false;
    }

    CKeyPool keypool;
    {
        LOCK(cs_KeyStore);
        int64_t nIndex;
        if (!ReserveKeyFromKeyPool(nIndex, keypool, internal) && !m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
            if (m_storage.IsLocked()) return false;
            WalletBatch batch(m_storage.GetDatabase());
            result = GenerateNewKey(batch, m_hd_chain, internal);
            return true;
        }
        KeepDestination(nIndex, type);
        result = keypool.vchPubKey;
    }
    return true;
}

bool LegacyScriptPubKeyMan::ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool fRequestedInternal)
{
    nIndex = -1;
    keypool.vchPubKey = CPubKey();
    {
        LOCK(cs_KeyStore);

        bool fReturningInternal = fRequestedInternal;
        fReturningInternal &= (IsHDEnabled() && m_storage.CanSupportFeature(FEATURE_HD_SPLIT)) || m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
        bool use_split_keypool = set_pre_split_keypool.empty();
        std::set<int64_t>& setKeyPool = use_split_keypool ? (fReturningInternal ? setInternalKeyPool : setExternalKeyPool) : set_pre_split_keypool;

        // Get the oldest key
        if (setKeyPool.empty()) {
            return false;
        }

        WalletBatch batch(m_storage.GetDatabase());

        auto it = setKeyPool.begin();
        nIndex = *it;
        setKeyPool.erase(it);
        if (!batch.ReadPool(nIndex, keypool)) {
            throw std::runtime_error(std::string(__func__) + ": read failed");
        }
        CPubKey pk;
        if (!GetPubKey(keypool.vchPubKey.GetID(), pk)) {
            throw std::runtime_error(std::string(__func__) + ": unknown key in key pool");
        }
        // If the key was pre-split keypool, we don't care about what type it is
        if (use_split_keypool && keypool.fInternal != fReturningInternal) {
            …