The invention disclosed herein is an in-circuit security system for electronic devices. The in-circuit security system incorporates identity credential verification, secure data and instruction storage, and secure data transmission capabilities. It comprises a single semiconductor chip, and is secured using industry-established mechanisms for preventing information tampering or eavesdropping, such as the addition of oxygen reactive layers. This invention also incorporates means for establishing security settings, profiles, and responses for the in-circuit security system and enrolled individuals. The in-circuit security system can be used in a variety of electronic devices, including handheld computers, secure facility keys, vehicle operation/ignition systems, and digital rights management.