Cryptology I (Autumn 2007)

Take-home exercises, 2nd set

Deadline: September 16th

Exercise 2a Break the following cryptogram, created using the text autokey cipher from an English text. You'll find the cryptogram in the file under your name. The length of the key is 5.
Silver Aabjõe Madis Abel Lidija Agen Erkki Alamäe Alexander Andrusenko Mart Aomets Kalmer Apinis Liisi Haav Roman Jagomägis Andres Kalle Diana Korsmik Magnus Leppik Jelena Makarova Avo Muromägi Jaan Neljandik Long Ngo Long Nguyen Hoang Margus Niitsoo Indrek Priks Kairi Schotter Ivo Seeba Andres Tiko Aleksandr Tkatšenko Ain Uljas Merli Uus Yanjun Yao

Exercise 2b We are given an encryption system where all plaintexts, ciphertexts, and keys are from the set {1,2,3,4,5,6}. Find H(K|C) and H(P|C). You'll find the encoding rules and distributions of plaintexts and keys in the file under your name.

Silver Aabjõe Madis Abel Lidija Agen Erkki Alamäe Alexander Andrusenko Mart Aomets Kalmer Apinis Liisi Haav Roman Jagomägis Andres Kalle Diana Korsmik Magnus Leppik Jelena Makarova Avo Muromägi Jaan Neljandik Long Ngo Long Nguyen Hoang Margus Niitsoo Indrek Priks Kairi Schotter Ivo Seeba Andres Tiko Aleksandr Tkatšenko Ain Uljas Merli Uus Yanjun Yao

Please submit the whole solution, including