Force encryption to be used when it is enabled.

Not doing this check would make it possible to skip encryption when it is enabled.

src/main/java/com/eu/habbo/habbohotel/gameclients/GameClient.java

@@ -24,6 +24,7 @@ public class GameClient {
     private final HabboEncryption encryption;
 
     private Habbo habbo;
+    private boolean handshakeFinished;
     private String machineId = "";
 
     public final ConcurrentHashMap<Integer, Integer> incomingPacketCounter = new ConcurrentHashMap<>(25);
@@ -56,6 +57,14 @@ public class GameClient {
         this.habbo = habbo;
     }
 
+    public boolean isHandshakeFinished() {
+        return handshakeFinished;
+    }
+
+    public void setHandshakeFinished(boolean handshakeFinished) {
+        this.handshakeFinished = handshakeFinished;
+    }
+
     public String getMachineId() {
         return this.machineId;
     }

src/main/java/com/eu/habbo/messages/incoming/handshake/CompleteDiffieHandshakeEvent.java

@@ -21,6 +21,7 @@ public class CompleteDiffieHandshakeEvent extends MessageHandler {
 
         byte[] sharedKey = this.client.getEncryption().getDiffie().getSharedKey(this.packet.readString());
 
+        this.client.setHandshakeFinished(true);
         this.client.sendResponse(new CompleteDiffieHandshakeComposer(this.client.getEncryption().getDiffie().getPublicKey()));
 
         this.client.getChannel().attr(GameServerAttributes.CRYPTO_CLIENT).set(new HabboRC4(sharedKey));

src/main/java/com/eu/habbo/messages/incoming/handshake/SecureLoginEvent.java

@@ -51,6 +51,11 @@ public class SecureLoginEvent extends MessageHandler {
         if (!Emulator.isReady)
             return;
 
+        if (Emulator.getCrypto().isEnabled() && !this.client.isHandshakeFinished()) {
+            Emulator.getGameServer().getGameClientManager().disposeClient(this.client);
+            return;
+        }
+
         String sso = this.packet.readString().replace(" ", "");
 
         if (Emulator.getPluginManager().fireEvent(new SSOAuthenticationEvent(sso)).isCancelled()) {