Patent ID: 8099769

Claim:
A method for controlling use of a secret key in a personalized device communicatively coupled to a main processor, said personalized device adapted to receive and transmit data messages, said method comprising: enabling a secure module to be communicatively coupled to said personalized device, said secure module storing said secret key, said secure module, when coupled to said personalized device, being connected via a first secure path to a secure input device and being connected via a second secure path to a secure display or secure portion of a display of said personalized device, wherein said first and second secure paths are logically isolated from said main processor; enabling a first output to be displayed on said secure display or said secure portion of said display of said personalized device under control of said secure module; displaying a second output under control of said main processor on said display of said personalized device or an external display at the same time as said first output, said main processor and said secure module being independently operable; and upon receipt of an external input via said secure input device indicative of a favorable comparison of said first and second outputs as displayed, controlling operation of said personalized device to obtain access to said secret key in said secure module for performing cryptographic operations.