Lecture 28 Computer Security

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Lecture 28Computer Security

• Phillip G. Bradford
• Computer Science
• The University of Alabama

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Outline

• One last word on E-Auctions
• More on Java Security

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Credits

• 1 Gary McGraw Edward W. Felten Securing
  Java, Wiley, 1999
• There is a new edition, too
• 2 Scott Oaks Java Security, OReilly, 2001

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Regulating E-Commerce through Certified
Contracts
Victoria Ungureanu Department of Computer
Science Rutgers University

• 11 AM, Friday March 21, 2003
• Houser 108

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More Discussion on Javas Security

• Language Restrictions
• No Pointers or pointer arithmetic
• Cant get the address of an object in memory
• Garbage collection, etc.
• What is Byte-code verification?
• Done when loads an untrusted class

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More Discussion on Javas Security

• What is Byte-code verification?
• Main goal
• No crashing JVM
• Checks validity of byte-codes operands
• No underflow/overflow of JVM stack
• Checks initialization of local variables, etc.

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More Discussion on Javas Security

• How secure is your SandBox?
• Java.lang.SecurityManager
• Security exceptions

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More Exam Review

• How does the Diffie-Hellman protocol work?
• What analytical problem does its security hinge
  upon?

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More Exam Review

• How does the RSA public crypto system work?
• What analytical problem does its security hinge
  upon ?

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More Exam Review

• Which Eulers theorem does the RSA public crypto
  system depend on?
• Why is it important here?

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More Exam Review

• In a block cipher, why might the key space be
  larger than the input block size?

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More Exam Review

• Why is security critical for Java?

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More Exam Review

• Discuss Pros and Cons of Kerberos design
• Generally private key only
• TGTs
• Central points of security/failure

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More Exam Review

• Why does our example of the Kerberos
  authentication-server ticket have
• Both the sender-id and sender-net-address?
• What attack can overcome this?

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More Exam Review

• Motivate open-outcry auctions
• Motivate sealed-bid auctions
• What does Yaos protocol use to allow
  comparisons?