An earlier encryption system for securing laptops from SCM Microsystems Inc., Fremont, CA (www.scmmicro.com). It used a 128-bit encryption key stored on a smart card that was inserted into the laptop's PC Card slot in order to encrypt/decrypt the data. If the laptop were stolen, the data could not be retrieved without the SwapCrypt card. The key was theoretically unbreakable, because it used an additional 160K bits of random data as part of the key.