Computer Laboratory

Daniel R. Thomas

Supervising - Security I

Prerequisite material

I have produced a worksheet with solutions covering prerequisite mathematics for Security I. This is a new worksheet and there are likely to be bugs, please report them and make suggestions for improvements. There may be cake or similar for those who do so. The source code is available.


Supervision questions last updated for 2013-2014.

If you write a program to solve any of these exercises I want to see the source code.

Supervision 1 - lectures 1-4: Cryptography, classic ciphers, block ciphers

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In order to communicate securely about supervisions we need a way of authenticating emails. All electronic submissions should be signed using your GPG key and encrypted to my work key D74933D9. This is an opportunity to learn to use encryption in a controlled environment so please do this properly we can discuss this at the start of the first supervision. You should submit an explanation of what you did to create and publish a key with your answers.

Exercises 1-4, 7-9 from the sheet.

Supervision 2 - lectures 5-7: Entity authentication, Access control

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Exercises: 11-14, 16, 17, 22, 23 and 25.

Supervision 3 - lectures 8-12: Operating system, software and network security; revision

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Exercises: 18-20, 30, 2004 Paper 3 Question 9, "Do software updates increase or decrease risk of successful attack?" and 3.21 from p109 of "Introduction to Modern Cryptography" by Jonathan Katz and Yehuda Lindell: Given two encryption schemes one of which is CPA secure (you don't know which) construct a scheme out of them which is CPA secure giving a full proof of your answer.