Cryptographically secure signature

FightSystem/FightSystem_Core/src/de/steamwar/fightsystem/utils/TechHiderWrapper.java

@@ -30,12 +30,24 @@ import de.steamwar.fightsystem.fight.FightTeam;
 import de.steamwar.fightsystem.states.FightState;
 import de.steamwar.fightsystem.states.StateDependent;
 import de.steamwar.fightsystem.states.StateDependentListener;
+import de.steamwar.sql.SteamwarUser;
 import de.steamwar.techhider.TechHider;
 import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.player.PlayerQuitEvent;
 
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.spec.SecretKeySpec;
+import java.io.File;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.file.Files;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
 import java.util.concurrent.ConcurrentHashMap;
 
 public class TechHiderWrapper extends StateDependent implements TechHider.LocationEvaluator, Listener {
@@ -43,12 +55,21 @@ public class TechHiderWrapper extends StateDependent implements TechHider.Locati
     public static final boolean ENABLED = !Config.OnlyPublicSchematics && !Config.test() && Config.TechhiderActive;
 
     private final ConcurrentHashMap<Player, Region> hiddenRegion = new ConcurrentHashMap<>();
+    private final ConcurrentHashMap<Player, Long> patterns = new ConcurrentHashMap<>();
     private final TechHider techHider;
+    private final Cipher cipher;
 
     public TechHiderWrapper() {
         super(ENABLED, FightState.Schem);
         techHider = new TechHider(this, Config.ObfuscateWith, Config.HiddenBlocks, Config.HiddenBlockEntities);
 
+        try {
+            cipher = Cipher.getInstance("AES_256/CFB/NoPadding");
+            cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(Files.readAllBytes(new File(System.getProperty("user.home"), "hullhider.key").toPath()), "AES"));
+        } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | IOException e) {
+            throw new SecurityException(e);
+        }
+
         new StateDependentListener(ENABLED, FightState.Schem, this);
         register();
     }
@@ -112,9 +133,8 @@ public class TechHiderWrapper extends StateDependent implements TechHider.Locati
     public TechHider.State check(Player player, int x, int y, int z) {
         if(hiddenRegion.computeIfAbsent(player, this::getHiddenRegion).inRegion(x, y, z)) {
             if(FightSystem.getHullHider().isBlockHidden(player, x, y, z)) {
-                long pattern = player.getUniqueId().getLeastSignificantBits();
                 int id = ((y&3) << 4) + ((z&3) << 2) + (x&3);
-                return (pattern & (1L << id)) == 0 ? TechHider.State.HIDE : TechHider.State.HIDE_AIR;
+                return (patterns.computeIfAbsent(player, this::getPattern) & (1L << id)) == 0 ? TechHider.State.HIDE : TechHider.State.HIDE_AIR;
             } else {
                 return TechHider.State.CHECK;
             }
@@ -123,6 +143,14 @@ public class TechHiderWrapper extends StateDependent implements TechHider.Locati
         }
     }
 
+    public long getPattern(Player player) {
+        try {
+            return ByteBuffer.wrap(cipher.doFinal(ByteBuffer.wrap(new byte[8]).putLong(SteamwarUser.get(player.getUniqueId()).getId()).array())).getLong();
+        } catch (IllegalBlockSizeException | BadPaddingException e) {
+            throw new SecurityException(e);
+        }
+    }
+
     @Override
     public boolean blockPrecise(Player player, int chunkX, int chunkY, int chunkZ) {
         return FightSystem.getHullHider().blockPrecise(player, chunkX, chunkY, chunkZ);