Add option to create an encrypted wallet

doc/release-notes-15006.md

@@ -0,0 +1,4 @@
+Miscellaneous RPC changes
+------------
+
+- `createwallet` can now create encrypted wallets if a non-empty passphrase is specified.

src/wallet/rpcwallet.cpp

@@ -2641,14 +2641,14 @@ static UniValue loadwallet(const JSONRPCRequest& request)
 
 static UniValue createwallet(const JSONRPCRequest& request)
 {
-    if (request.fHelp || request.params.size() < 1 || request.params.size() > 3) {
+    const RPCHelpMan help{
-        throw std::runtime_error(
+        "createwallet",
-            RPCHelpMan{"createwallet",
         "\nCreates and loads a new wallet.\n",
         {
             {"wallet_name", RPCArg::Type::STR, RPCArg::Optional::NO, "The name for the new wallet. If this is a path, the wallet will be created at the path location."},
             {"disable_private_keys", RPCArg::Type::BOOL, /* default */ "false", "Disable the possibility of private keys (only watchonlys are possible in this mode)."},
             {"blank", RPCArg::Type::BOOL, /* default */ "false", "Create a blank wallet. A blank wallet has no keys or HD seed. One can be set using sethdseed."},
+            {"passphrase", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "Encrypt the wallet with this passphrase."},
         },
         RPCResult{
             "{\n"
@@ -2660,7 +2660,10 @@ static UniValue createwallet(const JSONRPCRequest& request)
             HelpExampleCli("createwallet", "\"testwallet\"")
             + HelpExampleRpc("createwallet", "\"testwallet\"")
         },
-            }.ToString());
+    };
+
+    if (request.fHelp || !help.IsValidNumArgs(request.params.size())) {
+        throw std::runtime_error(help.ToString());
     }
     std::string error;
     std::string warning;
@@ -2670,7 +2673,20 @@ static UniValue createwallet(const JSONRPCRequest& request)
         flags |= WALLET_FLAG_DISABLE_PRIVATE_KEYS;
     }
 
+    bool create_blank = false; // Indicate that the wallet is actually supposed to be blank and not just blank to make it encrypted
     if (!request.params[2].isNull() && request.params[2].get_bool()) {
+        create_blank = true;
+        flags |= WALLET_FLAG_BLANK_WALLET;
+    }
+    SecureString passphrase;
+    passphrase.reserve(100);
+    if (!request.params[3].isNull()) {
+        passphrase = request.params[3].get_str().c_str();
+        if (passphrase.empty()) {
+            // Empty string is invalid
+            throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Cannot encrypt a wallet with a blank password");
+        }
+        // Born encrypted wallets need to be blank first so that wallet creation doesn't make any unencrypted keys
         flags |= WALLET_FLAG_BLANK_WALLET;
     }
 
@@ -2688,6 +2704,29 @@ static UniValue createwallet(const JSONRPCRequest& request)
     if (!wallet) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Wallet creation failed.");
     }
+
+    // Encrypt the wallet if there's a passphrase
+    if (!passphrase.empty() && !(flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
+        if (!wallet->EncryptWallet(passphrase)) {
+            throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Error: Wallet created but failed to encrypt.");
+        }
+
+        if (!create_blank) {
+            // Unlock the wallet
+            if (!wallet->Unlock(passphrase)) {
+                throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Error: Wallet was encrypted but could not be unlocked");
+            }
+
+            // Set a seed for the wallet
+            CPubKey master_pub_key = wallet->GenerateNewSeed();
+            wallet->SetHDSeed(master_pub_key);
+            wallet->NewKeyPool();
+
+            // Relock the wallet
+            wallet->Lock();
+        }
+    }
+
     AddWallet(wallet);
 
     wallet->postInitProcess();
@@ -4140,7 +4179,7 @@ static const CRPCCommand commands[] =
     { "wallet",             "addmultisigaddress",               &addmultisigaddress,            {"nrequired","keys","label","address_type"} },
     { "wallet",             "backupwallet",                     &backupwallet,                  {"destination"} },
     { "wallet",             "bumpfee",                          &bumpfee,                       {"txid", "options"} },
-    { "wallet",             "createwallet",                     &createwallet,                  {"wallet_name", "disable_private_keys", "blank"} },
+    { "wallet",             "createwallet",                     &createwallet,                  {"wallet_name", "disable_private_keys", "blank", "passphrase"} },
     { "wallet",             "dumpprivkey",                      &dumpprivkey,                   {"address"}  },
     { "wallet",             "dumpwallet",                       &dumpwallet,                    {"filename"} },
     { "wallet",             "encryptwallet",                    &encryptwallet,                 {"passphrase"} },

test/functional/wallet_createwallet.py

@@ -96,5 +96,28 @@ class CreateWalletTest(BitcoinTestFramework):
         assert_raises_rpc_error(-4, "Error: This wallet has no available keys", w5.getnewaddress)
         assert_raises_rpc_error(-4, "Error: This wallet has no available keys", w5.getrawchangeaddress)
 
+        self.log.info('New blank and encrypted wallets can be created')
+        self.nodes[0].createwallet(wallet_name='wblank', disable_private_keys=False, blank=True, passphrase='thisisapassphrase')
+        wblank = node.get_wallet_rpc('wblank')
+        assert_raises_rpc_error(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.", wblank.signmessage, "needanargument", "test")
+        wblank.walletpassphrase('thisisapassphrase', 10)
+        assert_raises_rpc_error(-4, "Error: This wallet has no available keys", wblank.getnewaddress)
+        assert_raises_rpc_error(-4, "Error: This wallet has no available keys", wblank.getrawchangeaddress)
+
+        self.log.info('Test creating a new encrypted wallet.')
+        # Born encrypted wallet is created (has keys)
+        self.nodes[0].createwallet(wallet_name='w6', disable_private_keys=False, blank=False, passphrase='thisisapassphrase')
+        w6 = node.get_wallet_rpc('w6')
+        assert_raises_rpc_error(-13, "Error: Please enter the wallet passphrase with walletpassphrase first.", w6.signmessage, "needanargument", "test")
+        w6.walletpassphrase('thisisapassphrase', 10)
+        w6.signmessage(w6.getnewaddress('', 'legacy'), "test")
+        w6.keypoolrefill(1)
+        # There should only be 1 key
+        walletinfo = w6.getwalletinfo()
+        assert_equal(walletinfo['keypoolsize'], 1)
+        assert_equal(walletinfo['keypoolsize_hd_internal'], 1)
+        # Empty passphrase, error
+        assert_raises_rpc_error(-16, 'Cannot encrypt a wallet with a blank password', self.nodes[0].createwallet, 'w7', False, False, '')
+
 if __name__ == '__main__':
     CreateWalletTest().main()