TPM

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Randy FortCS 265Trusted Platform Modules
April 19th, 2005
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What is Trusted Computing?

• In 1999, many industry heavyweights came together
  to form an industry group.

Mission Statement
to create a standard set of system hardware
based functions needed to establish trust on the
platform. 2
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What is a TPM?

• A chip integrated into the platform
• The (alleged) purpose is to provide more security
• It is a separate trusted co-processor

The TPM represents a separate trusted
coprocessor, whose state cannot be compromised by
potentially malicious host system software. IBM
Research Report 4
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Why?

• The theory is that software based key generation
  or storage will always be vulnerable to software
  attack, so private keys should be created,
  stored, and used by dedicated hardware
• Andy Dornan, Trusted Computing A Matter of Trust

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The Trusted Computing Group

• The Trusted Computing Group is a non-profit
  industry consortium, which develops hardware and
  software standards. It is funded by many member
  companies, including IBM, Intel, AMD, Microsoft,
  Sony, Sun, and HP among others.
• www.trustedcomputinggroup.org

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Attestation

• The TPM's most controversial feature is
  attestation, the ability to measure the state of
  a computer and send a signed message certifying
  that particular hardware or software is or isn't
  present. Most TC opponents fear that this will be
  abused by vendors 1.

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How?

• PKI private keys could be stored in the chip.
• PK signatures calculated in the chip itself,
  never visible outside
• Random number generators
• SHA-1 encryption
• Monotonic counters
• Process isolation (encrypted I/O, prevents
  keystroke loggers, screen scrapers.

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How?

• Protection from malware and detection of
  compromised systems. 4 Shows that syslogd has
  been compromised by a root kit.
• Tick counter, Timestamps are a security critical
  parameter in KERBEROS.
• Provide stronger 2 factor authentication.

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Whats new?

• Conceptually, not much. Most, if not all of the
  security ideas already exist
• What TPMs bring to the table is a secure sealed
  storage chip for private keys, on-chip crypto,
  and random number generators among others
• The state of the TPM can not be compromised by
  malicious host software

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Cons

• Advanced features will require O/S support.
• Microsoft's NGSCB (Longhorn Due 2006 ???)
• Will require rewrites to interface with the
  NEXUS.
• Potential for abuse by Software vendors.
• Is trusted computing just DRM on steroids?
• Is TC a security tool or cash flow weapon?
• Co-processor or Cop-processor?

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Pro vs. Con

• Great for Corporations and Government
• Prevents unauthorized software
• Helps prevent malware
• User privacy not a concern
• DRM lock-in less of a concern for companies or
  government

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Pro vs. Con

• Trusted Computing requires you to surrender
  control of your machine to the vendors of your
  hardware and software, thereby making the
  computer less trustworthy from the users
  perspective 11 Ross Anderson

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Windows Media Player 9 EULA

• "Digital Rights Management (Security). You agree
  that in order to protect the integrity of content
  and software protected by digital rights
  management ('Secure Content'), Microsoft may
  provide security related updates to the OS
  Components that will be automatically downloaded
  onto your computer. These security related
  updates may disable your ability to copy and/or
  play Secure Content and use other software on
  your computer. If we provide such a security
  update, we will use reasonable efforts to post
  notices on a web site explaining the update."

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• For years Bill Gates has dreamed of finding a
  way to make the Chinese pay for software, TC
  looks like being the answer to his prayer. 11
  Ross Anderson.

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Conclusion

• Increased security
• PKI
• Malware protection
• Attestation
• A very abuseable capability for software vendors

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Bibliography

• 1 Andy Doman, Trusted Computing A matter of
  Trust, http//www.networkmagazine.com/shared/arti
  cle/showArticle.jhtml?articleId22102889
• 2 DigitalIDWorld, "Assuring Networked Data and
  Application Reliability", Digital ID World
  Jan/Feb 2004 https//www.trustedcomputinggroup.o
  rg/press/1-3412425E_SC.pdf
• 4 Reiner Sailer, et al, , "The Role of TPM in
  Enterprise Security", https//www.trustedcomputin
  ggroup.org/press/news_articles/rc23363.pdf
• 11 Ross Anderson, http//www.againsttcpa.com/ind
  ex.shtml

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