Full disk encryption (FDE) technologies are designed to protect the data in case the platform is stolen. Such technologies can be either software-based or hardware-based. These technologies rely on the end-user providing a password on boots from certain states in order to unlock the access to data stored on device. However, FDE protects a computer's data-at-rest only when it is not decrypted yet, e.g. when it is being booted.
Another theft protections system is a software-based alerting mechanism. Software-based alerting mechanisms provide an immediate alert capability in order to protect against theft. The problem is that these mechanisms are susceptible to software-based attacks by thieves (e.g., turning off the WIFI radio), simple hardware-based attacks by thieves (e.g., pressing the platform's power button for 4 seconds).
Another theft protection system relies on discrete hardware components containing trigger-based alerting mechanisms. An example for this is a disk-on-key like component that gets plugged into the PC. However, this requires an additional plug-in device, and only works when the computer system is already active. In addition, a thief can easily destroy such components while keeping the platform intact, e.g. drown it in a glass of water, or bring down a hammer on it.