Confidentiality Policies and Integrity Policies

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Confidentiality Policies and Integrity Policies

• by Stefanie Wilcox

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Confidentiality Policies

• Prevent the unauthorized disclosure of
  information
• Unauthorized alteration of information
• The Bell-LaPadula Model

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The Bell-LaPadula Model

• Military-style classifications
• Security Classifications
• Security Clearances

TOP SECRET Tamara,Thomas Personnel
Files SECRET Sally, Samuel E-Mail
Files CONFIDENTIAL Claire,Clarence Activity Log
File UNCLASSIFIED Ulaley, Ursula Telephone List
File
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The Bell-LaPadula Model

• Simple Security Condition S(subject) can read
  O(object) if and only if lo lt ls, and S has
  read access to O.
• -Property S can write to O if and only if ls
  lt lo and S has write access to O.
• Basic Security Theorem A system is secure, if
  all transformations satisfy both.

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The Bell-LaPadula Model
TOP SECRET Tamara,Thomas Personnel
Files SECRET Sally, Samuel E-Mail
Files CONFIDENTIAL Claire,Clarence Activity Log
File UNCLASSIFIED Ulaley, Ursula Telephone List
File
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The Bell LaPadula Model

• Principle of Tranquility Subjects and objects
  may not change their security levels once they
  have been instantiated.
• Declassification problem
• Trusted Entities
• Strong Tranquility/Weak Tranquility

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Integrity Policies

• Commercial and Industrial firms are more
  concerned with accuracy than disclosure.
• Goals

1) Users will not write their own programs, but
will use existing production programs and
databases. 2) Programmers will develop and test
programs on a nonproduction system if they need
access to actual data, they will be given
production data via a special process, but will
use it on their development system. 3) A special
process must be followed to install a program
from the development system onto the production
system. 4) The special process in 3 must be
controlled and audited. 5) The managers and
auditors must have access to both the system
state and the system logs that are generated.
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Integrity Policies

• Principles of Operation

Separation of Duty Separation of
Function Auditing
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Integrity Policies

• Biba(1977)--Integrity Model
• Low-Water Mark
• Ring Policy
• Strict Integrity Policy

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HDI

• Formal Policy(Corporate)
• Informal (ERP software, Payroll)

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Bibliography
Bishop, Matt. Computer Security Art and Science.
2003 www.aw.com Hanover Direct Inc. Corporate
Information Systems Use Policy \www.hanoverdircect
.com