Add nthKey support

Keys can be imported using JSON or QR.

Wallet can be exported using JSON or QR.

Device supports testnet, signet and mainnet.

Only sh-wpkh (native Segwit) is supported.

Only multisig is supported.

Thumbnails generated with:
  convert nthkey-orig.png -channel RGB -negate -resize 300x300 -background white -gravity center -extent 200x200 -type grayscale nthkey@3x.png
  convert nthkey-orig.png -channel RGB -negate -resize 150x150 -background white -gravity center -extent 100x100 -type grayscale nthkey@2x.png
  convert nthkey-orig.png -channel RGB -negate -resize 75x75 -background white -gravity center -extent 50x50 -type grayscale nthkey.png

src/main/java/com/sparrowwallet/sparrow/AppController.java

@@ -938,7 +938,8 @@ public class AppController implements Initializable {
                 new CoboVaultSinglesig(), new CoboVaultMultisig(),
                 new PassportSinglesig(),
                 new KeystoneSinglesig(), new KeystoneMultisig(),
-                new CaravanMultisig());
+                new CaravanMultisig(),
+                new NthKeyMultisig());
         for(WalletImport importer : walletImporters) {
             try(FileInputStream inputStream = new FileInputStream(file)) {
                 if(importer.isEncrypted(file) && password == null) {

src/main/java/com/sparrowwallet/sparrow/control/WalletExportDialog.java

@@ -44,7 +44,7 @@ public class WalletExportDialog extends Dialog<Wallet> {
         if(wallet.getPolicyType() == PolicyType.SINGLE) {
             exporters = List.of(new Electrum(), new SpecterDesktop(), new Sparrow());
         } else if(wallet.getPolicyType() == PolicyType.MULTI) {
-            exporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new PassportMultisig(), new SpecterDesktop(), new BlueWalletMultisig(), new SpecterDIY(), new Sparrow());
+            exporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new PassportMultisig(), new SpecterDesktop(), new BlueWalletMultisig(), new SpecterDIY(), new Sparrow(), new NthKeyMultisig());
         } else {
             throw new UnsupportedOperationException("Cannot export wallet with policy type " + wallet.getPolicyType());
         }

src/main/java/com/sparrowwallet/sparrow/control/WalletImportDialog.java

@@ -54,7 +54,7 @@ public class WalletImportDialog extends Dialog<Wallet> {
             importAccordion.getPanes().add(importPane);
         }
 
-        List<WalletImport> walletImporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new SpecterDesktop(), new BlueWalletMultisig(), new Sparrow());
+        List<WalletImport> walletImporters = List.of(new CaravanMultisig(), new ColdcardMultisig(), new CoboVaultMultisig(), new Electrum(), new KeystoneMultisig(), new SpecterDesktop(), new BlueWalletMultisig(), new Sparrow(), new NthKeyMultisig());
         for(WalletImport importer : walletImporters) {
             FileWalletImportPane importPane = new FileWalletImportPane(importer);
             importAccordion.getPanes().add(importPane);

src/main/java/com/sparrowwallet/sparrow/io/NthKeyMultisig.java

@@ -0,0 +1,242 @@
+package com.sparrowwallet.sparrow.io;
+
+import com.google.common.io.CharStreams;
+import com.sparrowwallet.drongo.ExtendedKey;
+import com.sparrowwallet.drongo.KeyDerivation;
+import com.sparrowwallet.drongo.Utils;
+import com.sparrowwallet.drongo.policy.Policy;
+import com.sparrowwallet.drongo.policy.PolicyType;
+import com.sparrowwallet.drongo.protocol.ScriptType;
+import com.sparrowwallet.drongo.wallet.Keystore;
+import com.sparrowwallet.drongo.wallet.KeystoreSource;
+import com.sparrowwallet.drongo.wallet.Wallet;
+import com.sparrowwallet.drongo.wallet.WalletModel;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.*;
+import java.nio.charset.StandardCharsets;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+public class NthKeyMultisig implements WalletImport, KeystoreFileImport, WalletExport {
+    private static final Logger log = LoggerFactory.getLogger(NthKeyMultisig.class);
+
+    @Override
+    public String getName() {
+        return "nthKey Multisig";
+    }
+
+    @Override
+    public WalletModel getWalletModel() {
+        return WalletModel.NTHKEY;
+    }
+
+    @Override
+    public Keystore getKeystore(ScriptType scriptType, InputStream inputStream, String password) throws ImportException {
+        InputStreamReader reader = new InputStreamReader(inputStream, StandardCharsets.UTF_8);
+        NthKeyKeystore cck = JsonPersistence.getGson().fromJson(reader, NthKeyKeystore.class);
+
+        Keystore keystore = new Keystore("NthKey");
+        keystore.setSource(KeystoreSource.HW_AIRGAPPED);
+        keystore.setWalletModel(WalletModel.NTHKEY);
+
+        if(cck.xpub != null && cck.path != null) {
+            ExtendedKey.Header header = ExtendedKey.Header.fromExtendedKey(cck.xpub);
+            if(header.getDefaultScriptType() != scriptType) {
+                throw new ImportException("This wallet's script type (" + scriptType + ") does not match the " + getName() + " script type (" + header.getDefaultScriptType() + ")");
+            }
+            keystore.setKeyDerivation(new KeyDerivation(cck.xfp, cck.path));
+            keystore.setExtendedPublicKey(ExtendedKey.fromDescriptor(cck.xpub));
+        } else if(scriptType.equals(ScriptType.P2SH)) {
+            keystore.setKeyDerivation(new KeyDerivation(cck.xfp, cck.p2sh_deriv));
+            keystore.setExtendedPublicKey(ExtendedKey.fromDescriptor(cck.p2sh));
+        } else if(scriptType.equals(ScriptType.P2SH_P2WSH)) {
+            keystore.setKeyDerivation(new KeyDerivation(cck.xfp, cck.p2wsh_p2sh_deriv != null ? cck.p2wsh_p2sh_deriv : cck.p2sh_p2wsh_deriv));
+            keystore.setExtendedPublicKey(ExtendedKey.fromDescriptor(cck.p2wsh_p2sh != null ? cck.p2wsh_p2sh : cck.p2sh_p2wsh));
+        } else if(scriptType.equals(ScriptType.P2WSH)) {
+            keystore.setKeyDerivation(new KeyDerivation(cck.xfp, cck.p2wsh_deriv));
+            keystore.setExtendedPublicKey(ExtendedKey.fromDescriptor(cck.p2wsh));
+        } else {
+            throw new ImportException("Correct derivation not found for script type: " + scriptType);
+        }
+
+        return keystore;
+    }
+
+    private static class NthKeyKeystore {
+        public String p2sh_deriv;
+        public String p2sh;
+        public String p2wsh_p2sh_deriv;
+        public String p2wsh_p2sh;
+        public String p2sh_p2wsh_deriv;
+        public String p2sh_p2wsh;
+        public String p2wsh_deriv;
+        public String p2wsh;
+        public String xpub;
+        public String path;
+        public String xfp;
+    }
+
+    @Override
+    public String getKeystoreImportDescription() {
+        return "Import file created by using the Settings > Announce feature in nthKey.";
+    }
+
+    @Override
+    public String getExportFileExtension(Wallet wallet) {
+        return "txt";
+    }
+
+    @Override
+    public Wallet importWallet(InputStream inputStream, String password) throws ImportException {
+        Wallet wallet = new Wallet();
+        wallet.setPolicyType(PolicyType.MULTI);
+
+        int threshold = 2;
+        ScriptType scriptType = ScriptType.P2SH;
+        String derivation = null;
+
+        try {
+            List<String> lines = CharStreams.readLines(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
+            for (String line : lines) {
+                line = line.trim();
+                if (line.isEmpty()) {
+                    continue;
+                }
+
+                String[] keyValue = line.split(":");
+                if (keyValue.length == 2) {
+                    String key = keyValue[0].trim();
+                    String value = keyValue[1].trim();
+
+                    switch (key) {
+                        case "Name":
+                            wallet.setName(value.trim());
+                            break;
+                        case "Policy":
+                            threshold = Integer.parseInt(value.split(" ")[0]);
+                            break;
+                        case "Derivation":
+                        case "# derivation":
+                            derivation = value;
+                            break;
+                        case "Format":
+                            scriptType = ScriptType.valueOf(value.replace("P2SH_P2WSH"));
+                            break;
+                        default:
+                            if (key.length() == 8 && Utils.isHex(key)) {
+                                Keystore keystore = new Keystore("NthKey");
+                                keystore.setSource(KeystoreSource.HW_AIRGAPPED);
+                                keystore.setWalletModel(WalletModel.NTHKEY);
+                                keystore.setKeyDerivation(new KeyDerivation(key, derivation));
+                                keystore.setExtendedPublicKey(ExtendedKey.fromDescriptor(value));
+                                wallet.makeLabelsUnique(keystore);
+                                wallet.getKeystores().add(keystore);
+                            }
+                    }
+                }
+            }
+
+
+            Policy policy = Policy.getPolicy(PolicyType.MULTI, scriptType, wallet.getKeystores(), threshold);
+            wallet.setDefaultPolicy(policy);
+            wallet.setScriptType(scriptType);
+
+            if(!wallet.isValid()) {
+                throw new IllegalStateException("This file does not describe a valid wallet. " + getKeystoreImportDescription());
+            }
+
+            return wallet;
+        } catch(Exception e) {
+            log.error("Error importing " + getName() + " wallet", e);
+            throw new ImportException("Error importing " + getName() + " wallet", e);
+        }
+    }
+
+    @Override
+    public String getWalletImportDescription() {
+        return "Import file created by using the Settings > Announce -> Save as JSON Mainnet in nthKey.";
+    }
+
+    @Override
+    public void exportWallet(Wallet wallet, OutputStream outputStream) throws ExportException {
+        if(!wallet.isValid()) {
+            throw new ExportException("Cannot export an incomplete wallet");
+        }
+
+        if(!wallet.getPolicyType().equals(PolicyType.MULTI)) {
+            throw new ExportException(getName() + " import requires a multisig wallet");
+        }
+
+        boolean multipleDerivations = false;
+        Set<String> derivationSet = new HashSet<>();
+        for(Keystore keystore : wallet.getKeystores()) {
+            derivationSet.add(keystore.getKeyDerivation().getDerivationPath());
+        }
+        if(derivationSet.size() > 1) {
+            multipleDerivations = true;
+        }
+
+        try {
+           // TODO: should produce a JSON file like Specter does
+
+            // BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
+            // writer.append("# " + getName() + " setup file (created by Sparrow)\n");
+            // writer.append("#\n");
+            // writer.append("Name: ").append(wallet.getFullName()).append("\n");
+            // writer.append("Policy: ").append(Integer.toString(wallet.getDefaultPolicy().getNumSignaturesRequired())).append(" of ").append(Integer.toString(wallet.getKeystores().size())).append("\n");
+            // if(!multipleDerivations) {
+            //     writer.append("Derivation: ").append(wallet.getKeystores().get(0).getKeyDerivation().getDerivationPath()).append("\n");
+            // }
+            // writer.append("Format: ").append(wallet.getScriptType().toString().replace("P2SH-P2WSH", "P2WSH-P2SH")).append("\n");
+            // writer.append("\n");
+            //
+            // for(Keystore keystore : wallet.getKeystores()) {
+            //     if(multipleDerivations) {
+            //         writer.append("# derivation: ").append(keystore.getKeyDerivation().getDerivationPath()).append("\n");
+            //     }
+            //     writer.append(keystore.getKeyDerivation().getMasterFingerprint().toUpperCase()).append(": ").append(keystore.getExtendedPublicKey().toString()).append("\n");
+            //     if(multipleDerivations) {
+            //         writer.append("\n");
+            //     }
+            // }
+            //
+            // writer.flush();
+        } catch(Exception e) {
+            log.error("Error exporting " + getName() + " wallet", e);
+            throw new ExportException("Error exporting " + getName() + " wallet", e);
+        }
+    }
+
+    @Override
+    public String getWalletExportDescription() {
+        return "Export file that can be read by nthKey using the Settings > Import wallet > Import wallet JSON.";
+    }
+
+    @Override
+    public boolean isEncrypted(File file) {
+        return false;
+    }
+
+    @Override
+    public boolean isWalletImportScannable() {
+        return false;
+    }
+
+    @Override
+    public boolean isKeystoreImportScannable() {
+        return true;
+    }
+
+    @Override
+    public boolean isWalletExportScannable() {
+        return true;
+    }
+
+    @Override
+    public boolean walletExportRequiresDecryption() {
+        return false;
+    }
+}

src/main/java/com/sparrowwallet/sparrow/io/SpecterDesktop.java

@@ -73,7 +73,7 @@ public class SpecterDesktop implements WalletImport, WalletExport {
                             keystore.setWalletModel(walletModel);
                             if(walletModel == WalletModel.TREZOR_1 || walletModel == WalletModel.TREZOR_T || walletModel == WalletModel.KEEPKEY ||
                                 walletModel == WalletModel.LEDGER_NANO_S || walletModel == WalletModel.LEDGER_NANO_X ||
-                                walletModel == WalletModel.BITBOX_02 || walletModel == WalletModel.COLDCARD) {
+                                walletModel == WalletModel.BITBOX_02 || walletModel == WalletModel.COLDCARD || walletModel == WalletModel.NTHKEY) {
                                 keystore.setSource(KeystoreSource.HW_USB);
                             } else if(walletModel == WalletModel.BITCOIN_CORE) {
                                 keystore.setSource(KeystoreSource.SW_WATCH);