From 22a7d781528f4727ac6efbc31f4d29a0880570c1 Mon Sep 17 00:00:00 2001
From: bruno <bruno@brn.systems>
Date: Fri, 5 Apr 2024 15:49:26 +0200
Subject: [PATCH] The encoding is broken now

---
 .../systems/brn/chatencryptor/SecureChat.java | 56 ++++++++-----------
 1 file changed, 24 insertions(+), 32 deletions(-)

diff --git a/src/main/java/systems/brn/chatencryptor/SecureChat.java b/src/main/java/systems/brn/chatencryptor/SecureChat.java
index 143c374..7355fc9 100644
--- a/src/main/java/systems/brn/chatencryptor/SecureChat.java
+++ b/src/main/java/systems/brn/chatencryptor/SecureChat.java
@@ -19,57 +19,45 @@ import javax.crypto.NoSuchPaddingException;
 import java.nio.charset.StandardCharsets;
 import java.security.*;
 import java.time.Instant;
-import java.util.Base64;
+import java.util.Arrays;
 
 public class SecureChat implements ClientModInitializer {
 
     private PublicKey publicKey;
     private PrivateKey privateKey;
-    private Cipher encryptingCipher = null;
-    private Cipher decryptingCipher = null;
 
     private void initKeys() {
-        KeyPairGenerator kpg = null;
+        KeyPairGenerator kpg;
         try {
             kpg = KeyPairGenerator.getInstance("RSA");
         } catch (NoSuchAlgorithmException e) {
             throw new RuntimeException(e);
         }
-        kpg.initialize(1024);
+        kpg.initialize(512);
         KeyPair kp = kpg.genKeyPair();
         publicKey = kp.getPublic();
         privateKey = kp.getPrivate();
-
-        try {
-            encryptingCipher = Cipher.getInstance("RSA");
-            decryptingCipher = Cipher.getInstance("RSA");
-        } catch (NoSuchAlgorithmException e) {
-            throw new RuntimeException(e);
-        } catch (NoSuchPaddingException e) {
-            throw new RuntimeException(e);
-        }
-        try {
-            encryptingCipher.init(Cipher.ENCRYPT_MODE, publicKey);
-            decryptingCipher.init(Cipher.DECRYPT_MODE, privateKey);
-        } catch (InvalidKeyException e) {
-            throw new RuntimeException(e);
-        }
     }
 
     private boolean decryptChatMessage(Text message, @Nullable SignedMessage signedMessage, @Nullable GameProfile sender, MessageType.Parameters params, Instant receptionTimestamp) {
         TranslatableTextContent content = (TranslatableTextContent) message.getContent();
         String message_content = content.getArg(1).getString();
-        if(message_content.startsWith("BRNCrypt:")){
+        String player_name = content.getArg(0).getString();
+        if(message_content.startsWith("®") && message_content.endsWith("®")){
             try {
-                String strippedMessage = message_content.replace("BRNCrypt:", "");
-                byte[] decodedMessage = Base64.getDecoder().decode(strippedMessage);
-                String decryptedMessage = new String(decryptingCipher.doFinal(decodedMessage));
-                assert sender != null;
-                String outputMessage = "{" + sender.getName() + "} " + decryptedMessage;
+                String strippedMessage = message_content.replace("®", "");
+                byte[] decodedMessage = strippedMessage.getBytes(java.nio.charset.StandardCharsets.UTF_16);
+                byte[] unpaddedMessage = Arrays.copyOfRange(decodedMessage, 2, decodedMessage.length);
+                Cipher decryptingCipher = Cipher.getInstance("RSA");
+                decryptingCipher.init(Cipher.DECRYPT_MODE, privateKey);
+                decryptingCipher.update(unpaddedMessage);
+                String decryptedMessage = new String(decryptingCipher.doFinal());
+                String outputMessage = "{" + player_name + "} " + decryptedMessage;
                 MinecraftClient.getInstance().inGameHud.getChatHud().addMessage(Text.of(outputMessage));
                 return false;
             }
-            catch (IllegalBlockSizeException | BadPaddingException e){
+            catch (IllegalBlockSizeException | BadPaddingException | NoSuchAlgorithmException | NoSuchPaddingException |
+                   InvalidKeyException e){
                 return true;
             }
         }
@@ -77,14 +65,18 @@ public class SecureChat implements ClientModInitializer {
     }
 
     private String encryptChatMessage(String message) {
-        encryptingCipher.update(message.getBytes(StandardCharsets.UTF_8));
-        String encodedMessage = null;
+        String encodedMessage;
         try {
-            encodedMessage = Base64.getEncoder().withoutPadding().encodeToString(encryptingCipher.doFinal());
-        } catch (IllegalBlockSizeException | BadPaddingException e) {
+            Cipher encryptingCipher = Cipher.getInstance("RSA");
+            encryptingCipher.init(Cipher.ENCRYPT_MODE, publicKey);
+            encryptingCipher.update(message.getBytes(StandardCharsets.UTF_8));
+            byte[] encryptedMessage = encryptingCipher.doFinal();
+            encodedMessage = new String(encryptedMessage, java.nio.charset.StandardCharsets.UTF_16);
+        } catch (IllegalBlockSizeException | BadPaddingException | InvalidKeyException | NoSuchPaddingException |
+                 NoSuchAlgorithmException e) {
             throw new RuntimeException(e);
         }
-        return "BRNCrypt:" + encodedMessage;
+        return '®' + encodedMessage + '®';
     }
 
     @Override