Can You Trust Your Computer?

Who should your computer take its orders from? Most people think their computers should obey them, not obey someone else. With a plan they call “trusted computing,” large media corporations (including the movie companies and record companies), together with computer companies such as Microsoft and Intel, are planning to make your computer obey them instead of you. (Microsoft's version of this scheme is called Palladium.) Proprietary programs have included malicious features before, but this plan would make it universal.

Proprietary software means, fundamentally, that you don't control what it does; you can't study the source code, or change it. It's not surprising that clever businessmen find ways to use their control to put you at a disadvantage. Microsoft has done this several times: one version of Windows was designed to report to Microsoft all the software on your hard disk; a recent “security” upgrade in Windows Media Player required users to agree to new restrictions. But Microsoft is not alone: the KaZaa music-sharing software is designed so that KaZaa's business partner can rent out the use of your computer to its clients. These malicious features are often secret, but even once you know about them it is hard to remove them, since you don't have the source code.

In the past, these were isolated incidents. “Trusted computing” would make the practice pervasive. “Treacherous computing” is a more appropriate name, because the plan is designed to make sure your computer will systematically disobey you. In fact, it is designed to stop your computer from functioning as a general-purpose computer. Every operation may require explicit permission.

The technical idea underlying treacherous computing is that the computer includes a digital encryption and signature device, and the keys are kept secret from you. Proprietary programs will use this device to control which other programs you can run, which documents or data you can access, and what programs you can pass them to. These programs will continually download new authorization rules through the Internet, and impose those rules automatically on your work. If you don't allow your computer to obtain the new rules periodically from the Internet, some capabilities will automatically cease to function.

Of course, Hollywood and the record companies plan to use treacherous computing for Digital Restrictions Management (DRM), so that downloaded videos and music can be played only on one specified computer. Sharing will be entirely impossible, at least using the authorized files that you would get from those companies. You, the public, ought to have both the freedom and the ability to share these things. (I expect that someone will find a way to produce unencrypted versions, and to upload and share them, so DRM will not entirely succeed, but that is no excuse for the system.)

Making sharing impossible is bad enough, but it gets worse. There are plans to use the same facility for email and documents—resulting in email that disappears in two weeks, or documents that can only be read on the computers in one company.

Imagine if you get an email from your boss telling you to do something that you think is risky; a month later, when it backfires, you can't use the email to show that the decision was not yours. “Getting it in writing” doesn't protect you when the order is written in disappearing ink.

Imagine if you get an email from your boss stating a policy that is illegal or morally outrageous, such as to shred your company's audit documents, or to allow a dangerous threat to your country to move forward unchecked. Today you can send this to a reporter and expose the activity. With treacherous computing, the reporter won't be able to read the document; her computer will refuse to obey her. Treacherous computing becomes a paradise for corruption.

Word processors such as Microsoft Word could use treacherous computing when they save your documents, to make sure no competing word processors can read them. Today we must figure out the secrets of Word format by laborious experiments in order to make free word processors read Word documents. If Word encrypts documents using treacherous computing when saving them, the free software community won't have a chance of developing software to read them—and if we could, such programs might even be forbidden by the Digital Millennium Copyright Act.

Programs that use treacherous computing will continually download new authorization rules through the Internet, and impose those rules automatically on your work. If Microsoft, or the US government, does not like what you said in a document you wrote, they could post new instructions telling all computers to refuse to let anyone read that document. Each computer would obey when it downloads the new instructions. Your writing would be subject to 1984-style retroactive erasure. You might be unable to read it yourself.

You might think you can find out what nasty things a treacherous-computing application does, study how painful they are, and decide whether to accept them. Even if you can find this out, it would be foolish to accept the deal, but you can't even expect the deal to stand still. Once you come to depend on using the program, you are hooked and they know it; then they can change the deal. Some applications will automatically download upgrades that will do something different—and they won't give you a choice about whether to upgrade.

Today you can avoid being restricted by proprietary software by not using it. If you run GNU/Linux or another free operating system, and if you avoid installing proprietary applications on it, then you are in charge of what your computer does. If a free program has a malicious feature, other developers in the community will take it out, and you can use the corrected version. You can also run free application programs and tools on nonfree operating systems; this falls short of fully giving you freedom, but many users do it.

Treacherous computing puts the existence of free operating systems and free applications at risk, because you may not be able to run them at all. Some versions of treacherous computing would require the operating system to be specifically authorized by a particular company. Free operating systems could not be installed. Some versions of treacherous computing would require every program to be specifically authorized by the operating system developer. You could not run free applications on such a system. If you did figure out how, and told someone, that could be a crime.

There are proposals already for US laws that would require all computers to support treacherous computing, and to prohibit connecting old computers to the Internet. The CBDTPA (we call it the Consume But Don't Try Programming Act) is one of them. But even if they don't legally force you to switch to treacherous computing, the pressure to accept it may be enormous. Today people often use Word format for communication, although this causes several sorts of problems (see “We Can Put an End to Word Attachments”). If only a treacherous-computing machine can read the latest Word documents, many people will switch to it, if they view the situation only in terms of individual action (take it or leave it). To oppose treacherous computing, we must join together and confront the situation as a collective choice.

For further information about treacherous computing, see the “Trusted Computing” Frequently Asked Questions.

To block treacherous computing will require large numbers of citizens to organize. We need your help! Please support Defective by Design, the FSF's campaign against Digital Restrictions Management.


  1. The computer security field uses the term “trusted computing” in a different way—beware of confusion between the two meanings.

  2. The GNU Project distributes the GNU Privacy Guard, a program that implements public-key encryption and digital signatures, which you can use to send secure and private email. It is useful to explore how GPG differs from treacherous computing, and see what makes one helpful and the other so dangerous.

    When someone uses GPG to send you an encrypted document, and you use GPG to decode it, the result is an unencrypted document that you can read, forward, copy, and even reencrypt to send it securely to someone else. A treacherous-computing application would let you read the words on the screen, but would not let you produce an unencrypted document that you could use in other ways. GPG, a free software package, makes security features available to the users; they use it. Treacherous computing is designed to impose restrictions on the users; it uses them.

  3. The supporters of treacherous computing focus their discourse on its beneficial uses. What they say is often correct, just not important.

    Like most hardware, treacherous-computing hardware can be used for purposes which are not harmful. But these features can be implemented in other ways, without treacherous-computing hardware. The principal difference that treacherous computing makes for users is the nasty consequence: rigging your computer to work against you.

    What they say is true, and what I say is true. Put them together and what do you get? Treacherous computing is a plan to take away our freedom, while offering minor benefits to distract us from what we would lose.

  4. Microsoft presents Palladium as a security measure, and claims that it will protect against viruses, but this claim is evidently false. A presentation by Microsoft Research in October 2002 stated that one of the specifications of Palladium is that existing operating systems and applications will continue to run; therefore, viruses will continue to be able to do all the things that they can do today.

    When Microsoft employees speak of “security” in connection with Palladium, they do not mean what we normally mean by that word: protecting your machine from things you do not want. They mean protecting your copies of data on your machine from access by you in ways others do not want. A slide in the presentation listed several types of secrets Palladium could be used to keep, including “third party secrets” and “user secrets”—but it put “user secrets” in quotation marks, recognizing that this is somewhat of an absurdity in the context of Palladium.

    The presentation made frequent use of other terms that we frequently associate with the context of security, such as “attack,” “malicious code,” “spoofing,” as well as “trusted.” None of them means what it normally means. “Attack” doesn't mean someone trying to hurt you, it means you trying to copy music. “Malicious code” means code installed by you to do what someone else doesn't want your machine to do. “Spoofing” doesn't mean someone's fooling you, it means you're fooling Palladium. And so on.

  5. A previous statement by the Palladium developers stated the basic premise that whoever developed or collected information should have total control of how you use it. This would represent a revolutionary overturn of past ideas of ethics and of the legal system, and create an unprecedented system of control. The specific problems of these systems are no accident; they result from the basic goal. It is the goal we must reject.

As of 2015, the main method of distributing copies of anything is over the internet, and specifically over the web. Nowadays, the companies that want to impose DRM on the world want it to be enforced by programs that talk to web servers to get copies. This means that they are determined to control your browser as well as your operating system. The way they do this is through “remote attestation”—a facility with which your computer can “attest” to the web server precisely what software it is running, such that there is no way you can disguise it. The software it would attest to would include the web browser (to prove it implements DRM and gives you no way to extract the unencrypted data), the kernel (to prove it gives no way to patch the running browser), the boot software (to prove it gives no way to patch the kernel when starting it), and anything else relating to the security of the DRM companies' dominion over you.

Under an evil empire, the only crack by which you can reduce its effective power over you is to have a way to hide or disguise what you are doing. In other words, you need a way to lie to the empire's secret police. “Remote attestation” is a plan to force your computer to tell the truth to a company when its web server asks the computer whether you have liberated it.

As of 2015, treacherous computing has been implemented for PCs in the form of the “Trusted Platform Module”; however, for practical reasons, the TPM has proved a total failure for the goal of providing a platform for remote attestation to verify Digital Restrictions Management. Thus, companies implement DRM using other methods. At present, “Trusted Platform Modules” are not being used for DRM at all, and there are reasons to think that it will not be feasible to use them for DRM. Ironically, this means that the only current uses of the “Trusted Platform Modules” are the innocent secondary uses—for instance, to verify that no one has surreptitiously changed the system in a computer.

Therefore, we conclude that the “Trusted Platform Modules” available for PCs as of 2015 are not dangerous, and there is no immediate reason not to include one in a computer or support it in system software.

This does not mean that everything is rosy. Other hardware systems for blocking the owner of a computer from changing the software in it are in use in some ARM PCs as well as processors in portable phones, cars, TVs and other devices, and these are fully as bad as we expected.

This also does not mean that remote attestation is not a threat. If ever a device succeeds in implementing that, it will be a grave threat to users' freedom. The current “Trusted Platform Module” is harmless only because it failed in the attempt to make remote attestation feasible. We must not presume that all future attempts will fail too.

As of 2022, the TPM2, a new “Trusted Platform Module”, really does support remote attestation and can support DRM. The threat I warned about in 2002 has become terrifyingly real.

Remote attestation is actually in use by “Google SafetyNet” (now part of the “Play Integrity API”), which verifies that the Android operating system running in a snoop-phone is an official Google version.

This malicious functionality already makes it impossible to run some bank apps on GrapheneOS, which is a modified version of Android that eliminates some, though not all, of the nonfree software that Android normally contains.

A free version of Android, such as Replicant, would surely encounter the same obstacle. If you value your freedom enough to install Replicant, you might also refuse to tolerate any nonfree app (banking or not) on your computers. It is nonetheless unjust for Google to snoop on whether users have modified their operating system and dictate based on that what users can do with it.