Crypto: HW 1            Fall 2001            Michael Siff      

Due Thursday, September 13
    Read: Introduction and Chapter One of The Code Book by Simon Singh

  1. Find at least two non-trivial web sites that deal primarily with cryptologic issues. The sites should not be advertisements, news stories, nor Sarah Lawrence web sites (i.e., not any of my pages). Indicate the URL of the site and how you discovered the site. Familiarize yourself with navigating the site and with what the site has to offer. Be prepared to give a brief demonstration of one of the sites you find.

  2. Cryptologic exercises. For the following problems, indicate sources (book, computer, etc.) you use for assistance, if any.
    1. For each of the following, decipher the message and indicate the cryptosystem and key (where appropriate) used.

        HZIZS OZDIVMXV

        TP DH SW TVB CY MQ

    2. The following ciphertext has been encrypted using a shift cipher. (Spaces have been omitted from the original plaintext.) Write the corresponding plaintext (i.e., decrypt the message). What is the key?
          JSYVWGSVIERHWIZIRCIEVWEKS
      
    3. Describe a technique for cryptanalyzing any shift cipher. Is your technique practical for a person to do by hand? Would a computer help? Why or why not?


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