Transponder (Built-in keys)
WARNING: This page is about a different car, the 2011 Hyundai Elantra Touring. However, it is still accessible from the selected car via links, so may be relevant.
The transponder (A) has an advanced encryption algorithm. During the key teaching procedure, the transponder will be programmed with vehicle specific data. The vehicle specific data are written into the transponder memory. The write procedure is once only; therefore, the contents of the transponder can never be modified or changed.