computer security

1. Trusted Computing
Asmaa ALQassab Nagham ALLella Lubna
Supervised by Dr. Najlaa

2. WHO DO I TRUST?
• Today a computer trusts one of two entities
in a user and hacker model.
• The user is trusted and the hacker is not.
• But when does a computer know that the
user is not doing something harmful?
• With TC the user and the hacker are both
not trusted. This ensures that nothing is
done that can compromise the security of
the PC.

3. WHY TC?
“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”

4. TRUSTED COMPUTING: BASIC IDEA
• Addition of security hardware functionality to a
computer system to compensate for insecure
software.
• Enables external entities to have increased level of
trust that the system will perform as
expected/specified.
• Trusted platform = a computing platform with a
secure hardware component that forms a security
foundation for software processes.
• Trusted Computing = computing on a Trusted
Platform .

5. SO HOW DOES TC WORK?
• For TC to work you have to use the Trusted
Computing Module TPM which is a
hardware system where the core (root) of
trust in the platform will reside.
• TPM will be implemented using a security
microchip that handles security with
encryption.

6. 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.”

7. THE TRUSTED COMPUTING GROUP
• The Trusted Platform Module TPM is an
international standard for a secure crypto-
processor.
• The TPM technical specification was written by
a computer industry consortium called the
Trusted Computing Group TCG.
• 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.
•

8. 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].

9. 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.

10. 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.

11. WHAT’S 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

12. 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?

13. 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

14. 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 user’s
perspective” [11] Ross Anderson

15. 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."

16. “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.

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

18. BIBLIOGRAPHY
• [1] Andy Doman, Trusted Computing: A matter of Trust,
http://www.networkmagazine.com/shared/article/showArticle.jhtml?articleId=221028
89
• [2] DigitalIDWorld, "Assuring Networked Data and Application Reliability", Digital ID
World Jan/Feb 2004 https://www.trustedcomputinggroup.org/press/1-
3412425E_SC.pdf
•
• [4] Reiner Sailer, et al, , "The Role of TPM in Enterprise Security",
https://www.trustedcomputinggroup.org/press/news_articles/rc23363.pdf
• [11] Ross Anderson, http://www.againsttcpa.com/index.shtml