Private Information Protection based on UserTrusted Program

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Private Information Protectionbased on
User-Trusted Program

• Institute of Systems and Information
  Engineering/KYUSHU
• Kenichi Takahashi

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Introduction

• Wide spread of network environments
• e.g. cellular phone, wireless communication
  devices, refrigerator, television, etc...
• Hot Sport services at airports, shops

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What can we do ?
photo print book sales tourism info
situations
How is it used ?
creditcard for the payment
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Related works

• Symmetric-key, public-key, zero-knowledge
  algorithms, etc
• Digital signature, public-key infrastructure, etc
• The Platform for Private Preference
• defines a standard format to express privacy
  policy
• User agent can automate decision-making based on
  it
• Enterprise Privacy Authorization Language
• compels employees within the organization to keep
  privacy policy
• To provide rights of information access based on
  trustworthiness
• How do we compute trustworthiness?
• Does not make sure to prevent illegal information
  use

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A way of information check
check program
private information
user
service provider
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Ways of information check
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Public, private zone model

• We proposed public and private zone model
• which aims to realize user can protect own
  information by himself
• User and service providers are defined as agent
• Public zone is a space for dynamic service use
  and for executing trusted program
• Private zone is a space for protecting private
  information
• Security barrier is defined between public and
  private zone

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The overview of our model
From other agents
To other agents
public policy
interaction
Agent
client program attributes
public zone
get
public policies
client program
access check
security barrier
private zone
register
privacy policies
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Public zone

• realizes dynamic service use
• Service client program service program
• Client program is executed by users
• Service program is executed by the service
  provider
• Public policy client program attributes

public zone
public zone
security barrier
service program
3. communicate
2. execute
client program
pair
public policy
1. get
client program attributes
user
service provider
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Private zone

• Privacy policy
• permission purpose the user allows to use it
• trusted_prg methods the user allows to use it

private zone
public zone
security barrier
private information
use through trusted program
client program
privacy policy
service provider
user
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Issues

• How to create trusted programs ?
• How to protect trusted programs ?
• How to confirm the behaviour of trusted program ?
• How to protect service providers from trusted
  programs ?

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A way to create a trusted program

• Our model protects private information by the
  trusted program which we prepare
• How to create trusted programs ?
• To prepare the pattern which private information
  uses
• Service provider shows a process of private
  information use
• User extracts places where uses private
  information from the process
• User replace the place to his prepared pattern

payment (id, password) String p getPass
(id) if (password p) assign the
right of service use
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Protection of the trusted program

• A trusted program are executed by service
  provider
• The service provider can rewrite it easy
• Necessary to prevent illegal program rewriting
• Anti-tampering devices
• Software obfuscation, mobile cryptography

anti-tampering device
trusted-prg
encrypted-prg
kp
ks
encrypted-prg
kp
trusted-prg
user
execute
result
service provider
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Confirmation of trusted program

• The service provider checks private information
  by a trusted program
• The trusted program actually checks it?
• Protection of service provider
• There is some possibility of acting as malware
• Necessary to restrict trusted program behaviours

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Conclusion

• We proposed the basic model for private
  information protection
• Our model protects private information by users
  trusted program
• User can protect private information by own
  responsibility
• But some issues are remained
• Difficult to solve these issues
• But, these are interesting challenges

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Thank you for your attention