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Department of Information Technology

Lab assignments

Cryptoanalysis of the Vigenère cipher

Description

Follow the description from the slides presented in class.
Another (lengthy) description can be found here.


Your task

Find the plaintexts and keys for the 6 following cryptotexts:
cryptotext 1, cryptotext 2, cryptotext 3, cryptotext 4, cryptotext 5, cryptotext 6


Deliveries

Send your code and solutions to the lab assistant before the deadline.

This lab will be assessed through an oral examination:

  • Be prepared to show your code
  • Be prepared to explain your implementation
  • Be prepared to demonstrate your working solution

Extra: decipher crypto-L and crypto-Y


Dates

  • Lab session: February 7th and 8th
  • Deadline: February 13th at 17.00
  • Examination sessions: February 14th and 15th at 10.00

Help files

You can use the programming language of your choice, but Java or C/C++ are prefered. Here are some helper files (Note that they are only supplied as convenience, feel free to change or discard them):

Making and breaking RSA

Description and task

Follow the description here - slightly updated/clarified Feb 21.


Deliveries

Send your code and solutions to the lab assistant before the deadline.

This lab will be assessed through an oral examination:

  • Be prepared to show your code
  • Be prepared to explain your implementation
  • Be prepared to demonstrate your working solution

Dates

  • Lab session: February 19th and 20th.
  • Deadline: February 25th at 09.00
  • Examination sessions: March 5th and 6th.

Help files

You can use the programming language of your choice, but Java or C/C++ are prefered. Here is a helper file (note that it is only supplied as convenience, feel free to change or discard it): rsa-help.zip includes the GMP library files for Windows; a simple Java help file is also available.

A little Java code to encode and decode strings to BigIntegers: StringToNum.java.

Updated  2008-03-04 13:30:13 by Frédéric Haziza.