$ bitcoin-cli help walletpassphrasechange
walletpassphrasechange "oldpassphrase" "newpassphrase"

把钱包密码 'oldpassphrase' 改为 'newpassphrase'。

参数：
1. "oldpassphrase"（字符串）当前的密码
2. "newpassphrase"（字符串）新的密码

例子：
> bitcoin-cli walletpassphrase "old one" "new one"
> curl --user myusername:mypassword --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "walletpassphrasechange", "params": ["old one", "new one"] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/

源码剖析

walletpassphrase 对应的函数在文件 rpcserver.h 中被引用。

extern UniValue walletpassphrasechange(const UniValue& params, bool fHelp);

实现在文件 rpcwallet.cpp 中。

UniValue walletpassphrasechange(const UniValue& params, bool fHelp)
{
    if (!EnsureWalletIsAvailable(fHelp)) // 1. 确保钱包可用
        return NullUniValue;
    
    if (pwalletMain->IsCrypted() && (fHelp || params.size() != 2))
        throw runtime_error(
            "walletpassphrasechange \"oldpassphrase\" \"newpassphrase\"\n"
            "\nChanges the wallet passphrase from 'oldpassphrase' to 'newpassphrase'.\n"
            "\nArguments:\n"
            "1. \"oldpassphrase\"      (string) The current passphrase\n"
            "2. \"newpassphrase\"      (string) The new passphrase\n"
            "\nExamples:\n"
            + HelpExampleCli("walletpassphrasechange", "\"old one\" \"new one\"")
            + HelpExampleRpc("walletpassphrasechange", "\"old one\", \"new one\"")
        ); // 2. 帮助内容

    LOCK2(cs_main, pwalletMain->cs_wallet);

    if (fHelp)
        return true;
    if (!pwalletMain->IsCrypted())
        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Error: running with an unencrypted wallet, but walletpassphrasechange was called.");

    // TODO: get rid of these .c_str() calls by implementing SecureString::operator=(std::string)
    // Alternately, find a way to make params[0] mlock()'d to begin with.
    SecureString strOldWalletPass;
    strOldWalletPass.reserve(100);
    strOldWalletPass = params[0].get_str().c_str();

    SecureString strNewWalletPass;
    strNewWalletPass.reserve(100);
    strNewWalletPass = params[1].get_str().c_str();

    if (strOldWalletPass.length() < 1 || strNewWalletPass.length() < 1)
        throw runtime_error(
            "walletpassphrasechange <oldpassphrase> <newpassphrase>\n"
            "Changes the wallet passphrase from <oldpassphrase> to <newpassphrase>.");

    if (!pwalletMain->ChangeWalletPassphrase(strOldWalletPass, strNewWalletPass)) // 3. 更改钱包密码
        throw JSONRPCError(RPC_WALLET_PASSPHRASE_INCORRECT, "Error: The wallet passphrase entered was incorrect.");

    return NullUniValue;
}

1. 确保钱包可用

参考比特币 RPC 命令「fundrawtransaction」1. 确保钱包可用。

2. 帮助内容

参考比特币 RPC 命令「getbestblockhash」1. 帮助内容。

3. 更改钱包密码

更改钱包密码函数 pwalletMain->ChangeWalletPassphrase(strOldWalletPass, strNewWalletPass) 定义在文件 wallet.cpp 中。

bool CWallet::ChangeWalletPassphrase(const SecureString& strOldWalletPassphrase, const SecureString& strNewWalletPassphrase)
{
    bool fWasLocked = IsLocked(); // 获取当前钱包加密状态作为以前加密状态

    {
        LOCK(cs_wallet); // 钱包上锁
        Lock(); // 锁定（加密）钱包

        CCrypter crypter;
        CKeyingMaterial vMasterKey;
        BOOST_FOREACH(MasterKeyMap::value_type& pMasterKey, mapMasterKeys) // 遍历主密钥映射列表
        {
            if(!crypter.SetKeyFromPassphrase(strOldWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod)) // 从旧密码设置密钥
                return false;
            if (!crypter.Decrypt(pMasterKey.second.vchCryptedKey, vMasterKey)) // 解密
                return false;
            if (CCryptoKeyStore::Unlock(vMasterKey)) // 解锁
            {
                int64_t nStartTime = GetTimeMillis();
                crypter.SetKeyFromPassphrase(strNewWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod); // 使用新密码获取密钥
                pMasterKey.second.nDeriveIterations = pMasterKey.second.nDeriveIterations * (100 / ((double)(GetTimeMillis() - nStartTime))); // 计算迭代计数

                nStartTime = GetTimeMillis();
                crypter.SetKeyFromPassphrase(strNewWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod); // 第 2 次设置
                pMasterKey.second.nDeriveIterations = (pMasterKey.second.nDeriveIterations + pMasterKey.second.nDeriveIterations * 100 / ((double)(GetTimeMillis() - nStartTime))) / 2; // 重新计算迭代计数

                if (pMasterKey.second.nDeriveIterations < 25000) // 迭代计数最小 25000
                    pMasterKey.second.nDeriveIterations = 25000;

                LogPrintf("Wallet passphrase changed to an nDeriveIterations of %i\n", pMasterKey.second.nDeriveIterations);

                if (!crypter.SetKeyFromPassphrase(strNewWalletPassphrase, pMasterKey.second.vchSalt, pMasterKey.second.nDeriveIterations, pMasterKey.second.nDerivationMethod)) // 第 3 次设置
                    return false;
                if (!crypter.Encrypt(vMasterKey, pMasterKey.second.vchCryptedKey)) // 加密
                    return false;
                CWalletDB(strWalletFile).WriteMasterKey(pMasterKey.first, pMasterKey.second); // 把新密钥写入钱包数据库
                if (fWasLocked) // 若密码改变前未加密状态
                    Lock(); // 锁定（加密)
                return true;
            }
        }
    }

    return false;
}

参考链接