Improve session encryption handling

src/main/java/emu/nebula/net/GameSession.java

@@ -12,6 +12,7 @@ import emu.nebula.game.account.Account;
 import emu.nebula.game.account.AccountHelper;
 import emu.nebula.game.player.Player;
 import emu.nebula.util.AeadHelper;
+import emu.nebula.util.Utils;
 import lombok.Getter;
 import us.hebi.quickbuf.RepeatedByte;
 
@@ -22,6 +23,7 @@ public class GameSession {
     private Player player;
     
     // Crypto
+    private int encryptMethod; // 0 = gcm, 1 = chacha20
     private byte[] clientPublicKey;
     private byte[] serverPublicKey;
     private byte[] serverPrivateKey;
@@ -75,6 +77,7 @@ public class GameSession {
     
     public void calculateKey() {
         this.key = AeadHelper.generateKey(clientPublicKey, serverPublicKey, serverPrivateKey);
+        this.encryptMethod = Utils.randomRange(0, 1);
     }
     
     public String generateToken() {

src/main/java/emu/nebula/server/handlers/HandlerIkeReq.java

@@ -44,7 +44,7 @@ public class HandlerIkeReq extends NetHandler {
         // Create response
         var rsp = IKEResp.newInstance()
                 .setToken(session.getToken())
-                .setCipher(1) // 0 = gcm, 1 = chacha20
+                .setCipher(session.getEncryptMethod())
                 .setServerTs(Nebula.getCurrentTime())
                 .setPubKey(session.getServerPublicKey());
         

src/main/java/emu/nebula/server/routes/AgentZoneHandler.java

@@ -38,6 +38,7 @@ public class AgentZoneHandler implements Handler {
         
         byte[] sessionKey = AeadHelper.serverGarbleKey;
         boolean hasKey3 = false;
+        int encryptMethod = 0;
         
         // Get token
         String token = ctx.header("X-Token");
@@ -59,6 +60,7 @@ public class AgentZoneHandler implements Handler {
             
             // Set key
             sessionKey = session.getKey();
+            encryptMethod = session.getEncryptMethod();
             hasKey3 = true;
         }
         
@@ -80,7 +82,7 @@ public class AgentZoneHandler implements Handler {
             
             // Decrypt message
             if (hasKey3) {
-                message = AeadHelper.decryptChaCha(message, sessionKey);
+                message = AeadHelper.decrypt(message, sessionKey, encryptMethod);
                 offset = 10;
             } else {
                 message = AeadHelper.decryptBasic(message, sessionKey);
@@ -150,7 +152,7 @@ public class AgentZoneHandler implements Handler {
             
             // Encrypt
             if (hasKey3) {
-                result = AeadHelper.encryptChaCha(result, sessionKey);
+                result = AeadHelper.encrypt(result, sessionKey, encryptMethod);
             } else {
                 result = AeadHelper.encryptGCM(result, sessionKey);
                 result = AeadHelper.encryptBasic(result, sessionKey);

src/main/java/emu/nebula/util/AeadHelper.java

@@ -36,6 +36,24 @@ public class AeadHelper {
         return iv; 
     }
     
+    //
+
+    public static byte[] encrypt(byte[] data, byte[] sessionKey, int method) throws Exception {
+        if (method == 1) {
+            return encryptChaCha(data, sessionKey);
+        } else {
+            return encryptGCM(data, sessionKey);
+        }
+    }
+    
+    public static byte[] decrypt(byte[] data, byte[] sessionKey, int method) throws Exception {
+        if (method == 1) {
+            return decryptChaCha(data, sessionKey);
+        } else {
+            return decryptGCM(data, sessionKey);
+        }
+    }
+    
     // AES CBC
 
     public static byte[] encryptCBC(byte[] messageData) throws Exception {