Trusted Computing (TC) is intended to make me have confidence in your computer. That is, under TC, your PC can be considered trustworthy and therefore not a threat to my PC, and vice versa. To bring that about, our PCs must be protected from everyone, including ourselves, the rightful owners of the PCs. After all, the only way I can truly trust your PC is if you aren't allowed to mess it up, either purposely or otherwise. The care and feeding of our computers would be turned over to the nice folks who manufactured the hardware and wrote the software. We can trust them, right? The mind reels.
However well-meaning, the concept of TC is riddled with problems and drawing extremely strong reactions from both sides of the issue. Here's an example. Naturally, you and I, being computer geeks, don't like the idea of losing control of our property to the likes of, say, IBM, Intel, and Microsoft. Further, the first time we're locked out of our own files or not allowed to recover data to another disk due to TC, we'll hit the ceiling. So a proposed compromise is called "Owner Override," where, once the identity of the owner has been verified, the mechanisms of TC may be short-circuited. Well, the pro-TC folks rightly say Owner Override will defeat the whole purpose of TC.
The Trusted Computing Movement
There are several similar TC efforts underway within most of the major hardware and software companies. IBM, Intel, Microsoft, Hewlett-Packard (HP), and Advanced Micro Devices (AMD) have formed an organization called the Trusted Computing Platform Alliance (TCPA). The TCPA has a Trusted Computing Group (TCG) that's designing a Trusted Platform Module (TPM). Intel is designing TC hardware called LaGrande Technology (LT), and AMD is working on Secure Execution Mode (SEM).
The benevolent side of TC brings up some interesting concepts. Suppose you leave your TC-compliant laptop in a taxi. Since your laptop will only run if it receives the correct digital certificate each time it's turned on, you only have to contact the manufacturer and tell them to disallow the certificate. Now your laptop cannot be started, your data is safe, and surely your laptop will be returned to you because it's useless to anyone else.
How TC Works
TC all starts with new hardware that may be built into the next computer you buy. Sometimes called the "Fritz chip" (named after U.S. Congressman Fritz Hollings of South Carolina, who sponsored the Digital Millennium Act), an additional chip will check and verify all activities that take place on a computer. The Fritz chip will interact with all of your hardware and software applications and ensure that your PC has not been compromised. It will also check your serial numbers, licenses, and permissions and determine if they are legally yours to have and to use.
Software and data also come under the protection and control of TC. All data is encrypted and can be read only by the exact application that created it according to a manufacturer-supplied digital certificate. That means that even if someone got a copy of, say, one of your Word documents, they would not be able to read it. Only the copy of Word that was running on your PC would produce the digital certificate necessary to decrypt the document. On the other hand, if you were moving your documents to a new PC, you may have to create your own special certificates to allow the documents to be saved under the new PC's encryption.
The new hardware requires new operating system and application software. Together, the hardware and software aspire to secure computers through four features:
- Secure I/O--Uses checksums to verify software has not been maliciously modified.
- Memory Curtaining--Memory curtaining prevents programs from reading or writing each other's memory. This is not exactly new but has been heretofore handled by software. TC will protect memory through hardware.
- Sealed Storage--Sealed storage is the mechanism that encrypts data using a key derived from the combination of software and hardware being used.
- Remote Attestation--Remote attestation is the method a TC computer would use to determine if a remote TC computer had been changed and was no longer trustworthy. Remote attestation is probably the most controversial of the four TC features because it makes computers have to "check in" with manufacturers.
Digital Rights Management
An integral element of TC is Digital Rights Management (DRM). DRM consists of a number of strategies intended to control and restrict the use of digital media content like movies and music. In reference to their DRM media player, Microsoft claims "Windows Media digital rights management is a proven platform to protect and securely deliver content for playback on a computer, portable device, or network device." The truth is DRM is intended to protect digital media publishers and securely deliver otherwise lost revenue.
What the Critics Are Saying About TC
Most criticisms of TC are aimed at the new controls the manufacturers would have over the use of their products. According to Cambridge cryptographer Ross Anderson, "TC can support remote censorship. In general, digital objects created using TC systems remain under the control of their creators, rather than under the control of the person who owns the machine on which they happen to be stored. So someone who writes a paper that a court decides is defamatory can be compelled to censor it--and the software company that wrote the word processor could be ordered to do the deletion if she refuses. Given such possibilities, we can expect TC to be used to suppress . . . writings that criticize political leaders.
"Software suppliers can make it much harder for you to switch to their competitors' products. At a simple level, Word could encrypt all your documents using keys that only Microsoft products have access to; this would mean that you could only read them using Microsoft products, not with any competing word processor.
"The . . . most important benefit for Microsoft is that TC will dramatically increase the costs of switching away from Microsoft products (such as Office) to rival products (such as OpenOffice).
"The fundamental issue is that whoever controls the TC infrastructure will acquire a huge amount of power. Having this single point of control is like making everyone use the same bank, or the same accountant, or the same lawyer. There are many ways in which this power could be abused."
A commonly cited example of the threatening nature of Trusted Computing concerns digital media like songs and movies. Suppose a music publisher creates TC music files that can be played only 10 times without paying additional charges. The files are allowed to be played only on a TC-compliant player that will enforce the record company's rules via remote attestation. You can't open the files with another player because of sealed storage. Memory curtaining won't let you make a copy of the file while it's playing, and secure output prevents you from capturing the output that is sent to the speakers. Further, the record and movie companies keep logs of what you play and how often you play it.
Those opposed to DRM say "Transferring control of the use of media from consumers to a consolidated media industry will lead to loss of existing end-user rights, as well as stifling innovation in software and cultural productions. No current DRM technology includes a mechanism to enable fair use rights, though some DRM methods allow acts of copying which may coincidentally align with legal use rights. Arguably, a technology cannot, in principle, know what legal restrictions and rights apply in a specific jurisdiction, usage context, under an external contract, or to an individual author, owner, or publisher."
Is TC in Your Best Interest?
Generally, IT professionals don't like TC, IT corporations do, as does the government, but security measures, like locks, only keep the honest people out. A determined hacker can and will defeat any security mechanism. A highly integrated, proprietary, and complicated scheme like TC may even create avenues for malicious attack that could affect huge numbers of users in devastating ways (imagine if the permissions-granting infrastructure were compromised).
The term "Trusted Computing" is designed to suggest trustworthiness. This is like naming a ballistic missile "The Peacekeeper." And whether the motives behind TC are righteous or not, TC represents yet another assault on privacy and carries a huge potential for abuse. Created amid the atmosphere following terrorist events where the mere mention of "security" evokes shoulder-shrugging acquiescence, TC is indeed lipstick on a pig.