A computer system's security can be compromised in many ways a denial-of-service attack can make a server inoperable, a worm can destroy a user's private data, or an eavesdrop per can reap financial rewards by inserting himself in the communication link between a customer and her bank through a man-in-the-middle (MITM) attack. What all these scenarios have in common is that the adversary is an untrusted entity that attacks a system from the outside-we assume that the computers under attack are operated by benign and trusted users. But if we remove this assumption, if we allow anyone operating a computer system- from system administrators down to ordinary users-to compromise that system's security, we find ourselves in a scenario that has received comparatively little attention. Methods for protecting against MATE attacks are variously known as anti-tamper techniques, digital asset protection, or, more ...