more clearing private bits

src/main/java/com/sparrowwallet/drongo/Utils.java

@@ -111,6 +111,7 @@ public class Utils {
         int srcPos = isFirstByteOnlyForSign ? 1 : 0;
         int destPos = numBytes - length;
         System.arraycopy(src, srcPos, dest, destPos, length);
+        Arrays.fill(src, (byte)0);
         return dest;
     }
 

src/main/java/com/sparrowwallet/drongo/crypto/ECIESKeyCrypter.java

@@ -45,7 +45,7 @@ public class ECIESKeyCrypter implements AsymmetricKeyCrypter {
         byte[] hmacInput = Arrays.copyOfRange(decoded, 0, decoded.length - 32);
 
         if(!Arrays.equals(mac, hmac256(key_m, hmacInput))) {
-            throw new InvalidPasswordException();
+            throw new InvalidPasswordException("The password was invalid");
         }
 
         return aesKeyCrypter.decrypt(new EncryptedData(iv, ciphertext, null, null), new Key(key_e, null, null));

src/main/java/com/sparrowwallet/drongo/crypto/ECKey.java

@@ -699,6 +699,12 @@ public class ECKey implements EncryptableItem {
         return Utils.bigIntegerToBytes(getPrivKey(), 32);
     }
 
+    public void clear() {
+        for(int i = 0; i < priv.bitLength(); i++) {
+            priv.clearBit(i);
+        }
+    }
+
     /**
      * Returns the creation time of this key or zero if the key was deserialized from a version that did not store
      * that data.

src/main/java/com/sparrowwallet/drongo/crypto/Key.java

@@ -27,6 +27,5 @@ public class Key {
 
     public void clear() {
         Arrays.fill(keyBytes, (byte)0);
-        Arrays.fill(salt, (byte)0);
     }
 }

src/main/java/com/sparrowwallet/drongo/wallet/Keystore.java

@@ -202,4 +202,10 @@ public class Keystore {
             seed = seed.decrypt(key);
         }
     }
+
+    public void clearPrivate() {
+        if(hasSeed()) {
+            seed.clear();
+        }
+    }
 }

src/main/java/com/sparrowwallet/drongo/wallet/Wallet.java

@@ -198,4 +198,10 @@ public class Wallet {
             keystore.decrypt(key);
         }
     }
+
+    public void clearPrivate() {
+        for(Keystore keystore : keystores) {
+            keystore.clearPrivate();
+        }
+    }
 }