1. Presented by Mert Çetin
Trusted Computing
Presented by Mert Çetin

2. Trust: The Meaning Oxford English Dictionary:
Confidence in or reliance on some quality or attribute of a person or thing, or the truth of a statement.
Oxford Advanced Learners’ Dictionary:
The belief that sb/sth is good, sincere, honest, etc. and will not try to harm or deceive you
Longman
To believe that something is true without having any proof
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3. Trusted Computing Developed by Trusted Computing Group
Enforces a specific behaviour on a comp. system
Achieved by loading a hardware with a unique ID and unique master key
Deny even the owner knowledge and control
Extremely controversial
Not merely secured for the owner
But secured against the owner as well
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4. History TC: a broad term 2 main projects Microsoft Palladium
Operating system (add “trusted” computing to Windows)
Changed to NGSCB
TCPA: Trusted Computing Platform Alliance
Formed in 2003 to establish an industry standard
Published specifications
Changed to TCG
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5. Trusted Computing Group
Initiative started by:
AMD
Hewlett-Packard
IBM
Infineon
Intel
Microsoft
Sun Microsystems
Many others followed
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6. The need for Trusted Computing
Security Gap
Compromised Systems
Rouge Devices and services
Lost or stolen data
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7. Security Needs a New Model
Include the concept of identity
Build upon identity with strong authentication
Allow organizations to create trust relationships
Guarantee information confidentiality and integrity
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8. Trusted Platform Module
A microcontroller that stores keys, passwords and digital certificates
Is affixed to the motherboard of a PC
Ensures that the information stored is made more secure from external software attack and physical theft
Security processes, such as digital signature and key exchange, are protected
Access to data and secrets in a platform could be denied if the boot sequence is not as expected
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9. Applications and systems of TPM
TPMs offer improved, hardware-based security in numerous applications:
file and folder encryption
local password management
S-MIME
VPN and PKI authentication
wireless authentication for 802.1x and LEAP
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10. Cryptographic Algorithms
TPM specifications require RSA, SHA-1, and HMAC
AES is not required, but may be required in future versions
Use of symmetric encryption is not required
True random number generation is used for:
key generation
nonce creation
to strenghten pass phrase entropy
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11. TPM Architecture
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12. Key Concepts Endorsement Key Secure Input/Output
Memory Curtaining / protected execution
Sealed Storage
Remote Attestation
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13. Endorsement Key 2048 bit RSA public private key pair
Created randomly on chip at manufacture
Cannot be changed
Private key never leaves the chip
Public key is used for attestation and encryption
The key is used to allow executions of secure transactions
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14. Secure I/O A protected path between the computer user and the software
Aims to address threats posed by:
Keyloggers
Screen-grabbers
Using checksums to verify the I/O software is not tampered with
Malicious software could be identified
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15. Memory Curtaining Strong, hardware enforced memory isolation
To prevent programs to read/write one another’s memory
Today: intruder can read/alter PC Memory
In TC: even the OS cannot access curtained memory
Can be done in software
Rewriting of OS, drivers, applications
Hardware is better!
Backwards compatibility
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16. Sealed Storage
Protects private information by binding it to platform configuration info
Data can only be read by same combination of HW and SW
Solution to a major PC security falling:
inability to securely store cryptographic keys!
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17. Sealed Storage cont’d Generate keys based on: Keys need not be stored
Identity of the software requesting to use them
Identity of the computer the software is runing
Keys need not be stored
Generated when needed
Can work together with secure I/O and memory curtaining to ensure that your private data can only be read on your computer and with a particular software
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18. Remote Attestation
Allows changes to the user’s computer to be detected by authorized parties
Works by generating, in hardware, a cryptographic certificate attesting to the identity of the software currently running on a PC
Identity is represented by a cryptographic hash
When your software is altered other computers can refrain from sending private information to it
Combined with public key encryption
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19. Known Applications of TC
Windows Vista and Server 2008
BitLocker Drive Encryption
Encrypts complete volume
Protect hard-drive data
Plugging to a different system
Running different OS to modify boot data
Decrypt using TPM
Trusted Gentoo
give users the ability to store their cryptographic keys (e.g. ssh keys, gnupg keys) in hardware, to be released only to those applications the user wants the keys given to
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20. Possible Applications of TC
Digital Rights Management
e.g. a music file
Remote attestation: to enforce player
Sealed storage: to refuse to play on another software or on another computer
Curtained memory: prevent user from making unrestricted copy while playing
Secure I/O: prevent capturing what is being sent to the sound system
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21. Possible Applications of TC
Identity theft protection
Usernames and passwords: sniffable
TC creates assurance
e.g. Online banking via remote attestation
Preventing cheating in online games
remote attestation, secure I/O and memory curtaining could be used to verify that all players connected to a server were running an unmodified copy of the software
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22. Possible Applications of TC
Protection from viruses or spyware
Digital signature of software will allow users to identify applications modified by third parties that could add spyware to the software
Verification of remote computer for grid computing
TC could be used to guarantee participants in a grid are returning the results of the computations they claim to be instead of forging them
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23. Criticism of Trusted Computing
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24. Criticism of Trusted Computing
DRM
prevent users from freely sharing and using potentially copyrighted or private files without explicit permission
Software inter-operability and lock-in
unable to switch to a competing software
Word vs. OpenOffice
enforce use of specific programs
Internet Explorer
lock in
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25. Criticism of Trusted Computing
Unable to non-repudiate
that disappears in two weeks
documents that can only be read on the computers in one company
Censorship
refuse to let anyone read a specific document
Users unable to override
Requested but denied by TCG
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26. Criticism of Trusted Computing
Users may be forced to use proprietary software
May require the operating system to be specifically authorized by a particular company
May require every program to be specifically authorized by the operating system developer
Cannot install/use free software on those machines
Practicality and Reliability
No opportunity of recovery in the case of malfunction
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27. Criticism of Trusted Computing
Loss of anonymity
A TC system can uniquely attest to its own identity
Possible for others to zero in the user’s identity
Voluntarily or unvoluntarily
Lose expectations of anonymity when using the Internet
Chilling effect on:
political free speech
the ability of journalists to use anonymous sources
other areas where the public needs protection from retaliation through anonymity
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28. Solution to anonymity Direct anonymous attestation
enables the remote authentication of a trusted platform while preserving the platform's privacy
uses a zero-knowledge proof
makes use of:
Camenisch-Lysyanskaya signature scheme
discrete logarithm-based proofs of knowledge thereon
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29. Figures
It’s happening!
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30. Trustworthy or Treacherous Computing?
The decision is yours..
Any questions?
CS532 - Sabancı University 2008