Validate that XMR subaddress view key matches the main address

core/src/main/java/bisq/core/xmr/knaccc/monero/address/WalletAddress.java

@@ -7,6 +7,10 @@
 import bisq.core.xmr.org.nem.core.crypto.ed25519.arithmetic.Ed25519Group;
 import bisq.core.xmr.org.nem.core.crypto.ed25519.arithmetic.Ed25519GroupElement;
 
+import com.google.common.annotations.VisibleForTesting;
+
+import java.util.Arrays;
+
 import static bisq.core.xmr.knaccc.monero.address.ByteUtil.concat;
 import static bisq.core.xmr.knaccc.monero.address.ByteUtil.hexToBytes;
 import static bisq.core.xmr.knaccc.monero.address.ByteUtil.longToLittleEndianUint32ByteArray;
@@ -121,7 +125,30 @@ public static String getSubaddressBase58(Scalar privateViewKey,
 
     }
 
-    public String getSubaddressBase58(String privateViewKeyHex, long accountId, long subaddressId) {
+    public String getSubaddressBase58(String privateViewKeyHex, long accountId, long subaddressId) throws InvalidWalletAddressException {
+        if (!checkPrivateViewKey(privateViewKeyHex)) {
+            throw new InvalidWalletAddressException("Wrong private view key for main address");
+        }
         return getSubaddressBase58(new Scalar(privateViewKeyHex), hexToBytes(getPublicSpendKeyHex()), accountId, subaddressId);
     }
+
+    @VisibleForTesting
+    boolean checkPrivateViewKey(String privateViewKey) {
+        return isPrivateKeyReduced(privateViewKey) && doesPrivateKeyResolveToPublicKey(privateViewKey, this.publicViewKeyHex);
+    }
+
+    @VisibleForTesting
+    static boolean isPrivateKeyReduced(String privateKey) {
+        byte[] input = hexToBytes(privateKey);
+        byte[] reduced = CryptoUtil.scReduce32(input);
+        return Arrays.equals(input, reduced);
+    }
+
+    @VisibleForTesting
+    static boolean doesPrivateKeyResolveToPublicKey(String privateKey, String publicKey) {
+        Scalar m = new Scalar(privateKey);
+        Ed25519GroupElement M = G.scalarMultiply(new Ed25519EncodedFieldElement(m.bytes));
+        byte[] generatedPubKey = M.encode().getRaw();
+        return Arrays.equals(generatedPubKey, hexToBytes(publicKey));
+    }
 }

core/src/test/java/knaccc/monero/address/CryptoUtilTest.java → core/src/test/java/bisq/core/xmr/knaccc/monero/address/CryptoUtilTest.java

@@ -15,7 +15,7 @@
  * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
  */
 
-package knaccc.monero.address;
+package bisq.core.xmr.knaccc.monero.address;
 
 import bisq.core.xmr.knaccc.monero.crypto.CryptoUtil;
 

core/src/test/java/knaccc/monero/address/WalletAddressTest.java → core/src/test/java/bisq/core/xmr/knaccc/monero/address/WalletAddressTest.java

@@ -15,13 +15,13 @@
  * along with Bisq. If not, see <http://www.gnu.org/licenses/>.
  */
 
-package knaccc.monero.address;
-
-import bisq.core.xmr.knaccc.monero.address.WalletAddress;
+package bisq.core.xmr.knaccc.monero.address;
 
 import org.junit.Test;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
 
 public class WalletAddressTest {
     @Test
@@ -30,6 +30,7 @@ public void testWalletAddress() throws WalletAddress.InvalidWalletAddressExcepti
         WalletAddress walletAddress = new WalletAddress(mainAddress);
 
         String privateViewKeyHex = "7b37d8922245a07244fd31855d1e705a590a9bd2881825f0542ad99cdaba090a";
+        String publicViewKeyHex = "3cd5a3079e8b4cff3630ce16bfda6eebb2da86169accdb93206a92a58d586faa";
 
         System.out.println("subaddress for account index 0, subaddress index 1: "
                 + walletAddress.getSubaddressBase58(privateViewKeyHex, 0, 1));
@@ -46,5 +47,25 @@ public void testWalletAddress() throws WalletAddress.InvalidWalletAddressExcepti
         assertEquals(walletAddress.getSubaddressBase58(privateViewKeyHex, 0, 1), addr01);
         assertEquals(walletAddress.getSubaddressBase58(privateViewKeyHex, 1, 0), addr10);
         assertEquals(walletAddress.getSubaddressBase58(privateViewKeyHex, 1, 1), addr11);
+
+        assertTrue(walletAddress.checkPrivateViewKey(privateViewKeyHex));
+        assertTrue(WalletAddress.doesPrivateKeyResolveToPublicKey(privateViewKeyHex, publicViewKeyHex));
+        assertFalse(WalletAddress.doesPrivateKeyResolveToPublicKey(privateViewKeyHex, privateViewKeyHex));
+
+        assertTrue(WalletAddress.doesPrivateKeyResolveToPublicKey(
+                "a82a9017a1d259c71f5392ad9091b743b86dac7a21f5e402ea0a55e5c8a6750f",
+                "bdc158199c8933353627d54edb4bbae547dbbde3130860d7940313210edca0a6"));
+
+        assertTrue(WalletAddress.doesPrivateKeyResolveToPublicKey(
+                "dae1bceeb2563b8c376f8e0456e5fe7aa3d6291b38ace18c6ad5647424a3b104",
+                "d17698d07fe9edbc41552299b90a93de73bb1bd4b94b8083af0bbe3a1931e2ec"));
+
+        assertFalse(WalletAddress.doesPrivateKeyResolveToPublicKey(
+                "0000111122223333444455556666777788889999AAAABBBBCCCCDDDDEEEEFFFF",
+                "0000111122223333444455556666777788889999AAAABBBBCCCCDDDDEEEEFFFF"));
+
+        String nonReducedPrivateKey = "680bceef3ca8b2ca1a9a29283c184f6f590a9bd2881825f0542ad99cdaba091a";
+        assertFalse(WalletAddress.isPrivateKeyReduced(nonReducedPrivateKey));
+        assertTrue(WalletAddress.isPrivateKeyReduced(privateViewKeyHex));
     }
 }

desktop/src/main/java/bisq/desktop/components/paymentmethods/XmrForm.java

@@ -251,17 +251,21 @@ public void updateFromInputs() {
             xmrAccountDelegate.setPrivateViewKey(privateViewKeyInputTextField.getText());
             xmrAccountDelegate.setAccountIndex(accountIndex.getText());
             xmrAccountDelegate.setSubAddressIndex(subAddressIndex.getText());
+            subAddressTextField.getStyleClass().remove("error-text");
             if (accountIndex.validate() && subAddressIndex.validate()
                     && mainAddressTextField.validate()
                     && privateViewKeyInputTextField.validate()
                     && mainAddressTextField.getText().length() > 0
                     && privateViewKeyInputTextField.getText().length() > 0) {
                 try {
                     xmrAccountDelegate.createAndSetNewSubAddress();
+                    subAddressTextField.setText(xmrAccountDelegate.getSubAddress());
                 } catch (Exception ex) {
-                    log.warn(ex.toString());
+                    log.warn(ex.getMessage());
+                    String[] parts = ex.getMessage().split(":");
+                    subAddressTextField.setText(parts.length > 0 ? parts[parts.length-1] : ex.getMessage());
+                    subAddressTextField.getStyleClass().add("error-text");
                 }
-                subAddressTextField.setText(xmrAccountDelegate.getSubAddress());
             } else {
                 xmrAccountDelegate.setSubAddress("");
                 subAddressTextField.setText("");