Systems and methods for protecting electronic and other sensitive devices in the event of security breaches such as physical intrusion or access, tampering, and attempts at reverse engineering. One aspect of the present invention provides security systems and methods that utilize an active security measure that can identify a security breach and respond with a protective action. Protective actions may include erasure or randomizing of data or software, activation of an alarm or signal (such as at a remote location), or destruction of any portion of a protected device or circuit or the like.