Modifying security state with highly secured devices

Abstract

Some embodiments of the invention provide a method for authenticating a security device (e.g., a smart card or other highly secured device) to modify a security state (e.g., unlocking, decrypting, etc.) at a target device (e.g., laptop computers, mobile phones, tablets, etc.). In some embodiments, the security device does not have a volatile storage for storing volatile parameters for the particular device to use to perform the authentication process. The method of some embodiments sends an encrypted challenge to the security device, in which the encrypted challenge can only be decrypted by the security device. The method receives a response and modifies accessibility for the target device when the response is a valid response. The method of some embodiments determines that a response is valid based on the decrypted contents of the response and/or based on a period of time between the issuance of the challenge and the received response.