Native cryptography support using mbed TLS

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftCipherDecoder.java

@@ -17,7 +17,7 @@ public class MinecraftCipherDecoder extends ByteToMessageDecoder {
 
     @Override
     protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
-        ByteBuf decrypted = ctx.alloc().buffer();
+        ByteBuf decrypted = ctx.alloc().buffer(in.readableBytes());
         try {
             cipher.process(in, decrypted);
             out.add(decrypted);

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftCipherEncoder.java

@@ -18,6 +18,11 @@ public class MinecraftCipherEncoder extends MessageToByteEncoder<ByteBuf> {
         cipher.process(msg, out);
     }
 
+    @Override
+    protected ByteBuf allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg, boolean preferDirect) throws Exception {
+        return ctx.alloc().directBuffer(msg.readableBytes());
+    }
+
     @Override
     public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
         cipher.dispose();