Portable Device Security via BIOS Password Segmentation

The patent divides the security verification process into two independent stages: first verifying a first password to access a first protection variable, then verifying a second password to access a second protection variable. This segmentation ensures that even if one stage is compromised, the other remains protected, thereby reducing the overall probability of the device being cracked while maintaining operational capability.

The patent sets the first protection variable in the read-only memory before the device is fully powered on or before normal operations begin. This preliminary action ensures that the security mechanism is already in place and configured, allowing the system to perform password checking without requiring continuous power supply to the basic input/output system, thus reducing the probability of being cracked.

The patent implements a two-stage password verification process with separate protection variables stored in read-only memory. The first password checks against the first protection variable, and the second password checks against the second protection variable. This segmentation increases the security level by requiring multiple independent verification steps, making it more resistant to various attack scenarios while maintaining a relatively simple overall structure.

The patent combines multiple security mechanisms (first password verification, second password verification, protection variables in read-only memory, keyboard controller interventions) into a composite security system. This composite approach integrates different security layers that work together to provide enhanced protection against multiple attack scenarios while managing complexity through systematic organization.