Techniques for protecting resources of a client from theft or unauthorized access. A BIOS agent stores policy data within a BIOS of the client. The BIOS agent is one or more software modules operating in the BIOS of the client. The policy data describes one or more security policies which the client is to follow. In response to the client following at least one of the one or more security policies, a persistent storage medium of the client is locked by instructing a controller of the persistent storage medium to deny, to any entity, access to data stored on the persistent storage medium unless the entity supplies, to the controller, a recognized authentication credential. In this way, a malicious user without access to the recognized authentication credential cannot access the data stored on the persistent storage medium, even if the persistent storage medium is removed from the client.