HTW Berlin Fachbereich 4 Internationaler Studiengang Internationale Medieninformatik (Bachelor) Aktuelles - Medien: Kryptographie Winter Term 2009/10

Lab 1: Simple Ciphers

Try your hand on the following ciphertexts! Can you discover the plaintext? Don't use any of the online tools available. You need to describe the process by which you solved the ciphers.

1. What is the plaintext for the following ciphertext that was produced using a Caesar Code?
   
   MABL BL T OXKR MKBOBTE VHWX MH UKXTD
   
   
2. What is the plaintext for the following ciphertext that was produced using a Scytale?
   
   ISADTPIHEHNNCSDIROOILTAIHTAEASNFEZCSWESSNISFIUKTUJSESTCRCKE!
   
   Describe in your report how you cracked this cipher!
   
   
3. What is the plaintext for the following ciphertext that was produced using a monoalphabetic cipher?
   
   53==+305))6*;4826)4=.)4=);806*;48+8/60))85;;]8*;:=*8+83(88)5*+;46(;88*96
   *?;8)*=(;485);5*+2:*=(;4956*2(5*-4)8/8*;4069285);)6+8)4==;1(=9;480
   81;8:8=1;48+85;4)485+528806*81(=9;48;(88;4(=?34;48)4=;161;:188;=?;
   
   
4. Using a Vigenère code and the keyword enigma, determine the plaintext for this ciphertext:
   
   XUQYU SEAMG EYGBL KFOFE MGWIJ LWAWN SJBNQ KILEU
   DDEAL ORYSH LUZTM GQYET MYTTA TXUIZ TAVQ
   
   
5. For (bored) experts: we encoded this using Vigenère code and lost the key. What might it be?
   
   TDHVK XWNQI OJMVE MNVUC XZPMY SDTPR XWHCT UDBQM KSYWX NWPCQ RLISI AOLJA WGUYE FHWQH QCOVL NNLDO DMYYM VIVMG AUOHU HZXMZ UTKQG

Your report is due in the Moodle Room by 23.00 next Tuesday. You need to describe what method you used to crack the code. If you were unable to crack it, please record what you did to attempt to solve the code. You may work in groups of two, but each of you must hand in their own copy of the report.

This material is jointly prepared by Dr. Hermann Thiel and Prof. Dr. Debora Weber-Wulff. Much of the material comes from other sources and is denoted by the copyright notices on the individual pages