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Section1 - Lign 17 Section worksheets Friday, January...

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Unformatted text preview: Lign 17 Section worksheets Friday, January 14th and Tuesday, January 18th, 2011 Problem Naught: A Railfence Warmup A Confession: My favorite video game is embarrassingly old. I’m trying to cover it up using a railfence cipher in the enciphered message below: TGFAITHEZONIENECAMLDLAOEEODRF 1. How many letters are there in the message? _______ 2. How many rows were used to encode it? ________ 3. What is the message? 4. Encipher the name of your favorite game using a railfence cipher of your choosing. Write the result here: Problem 1: The Hooloovoo According to the Hitchhiker’s Guide to the Galaxy, a Hooloovoo is a hyper ­intelligent shade of the Colour Blue. One Hooloovoo in particular was involved with the design and construction of the spaceship Heart of Gold with its new Infinite Improbability Drive. In 6 ­digit RGB Hexadecimal, this Hooloovoo can be represented as: 1208C7 You are responsible for transmitting the Hooloovoo safely to Milliways, the Restaurant at the End of the Universe. In order to make sure that it is invulnerable to industrial espionage (the precise mechanics of the Infinite Improbability Drive are valuable beyond your wildest dreams), it suggests that you encipher its RGB value using a 2 ­place shift ­cipher, as follows: 1 Plaintext Value Shift ­Cipher Value Double ­Application 0 2 1 3 2 4 3 5 4 6 5 7 6 8 7 9 8 A 9 B A C B D C E D F E 0 F 1 1. What is the Hooloovoo’s RGB value in ciphertext? ______________________ 2. You notice a problem with the Hooloovoo’s idea, in that it would be incredibly easy for an eavesdropper to find the key: there are very few unique hexadecimal _____ (Note: one possible, but ineffective, shift ­ciphers. How many are there? cipher is a shift of 0 places.) 3. Your solution to this problem is to encrypt the Hooloovoo twice using the shift ­ cipher the Hooloovoo proposed. Complete the table above to show the resulting cipher alphabet. Was this a good idea on your part? _______ 2 4. If you applied the initial shift ­cipher eight times, what would happen? 5. What about your suggested double ­application cipher? Problem B: The Most Perilous Dame Figure 1 Figure 2 Figure 3 Figure 1: Princess Peach Toadstool is well known for being perhaps the most kidnapped woman in videogame history. One of the reasons for this is, of course, the large volume of unencrypted correspondence she sends to Figure 2, Mario. 1. Suppose that you are Princess Toadstool’s Chief Cryptographer (Figure 3, Toad). You encourage her to encipher her messages using a Mono alphabetic Substitution Cipher with a Key phrase. The key ­phrase you want her to use is “MUSHROOM”. Provide the mapping from the plaintext alphabet to the ciphertext alphabet. Plaintext alphabet A B C D E F G H I J K L M N O P Q R S T U V W X Ciphertext alphabet 2. Now, encipher the following message, which Princess Toadstool wishes to send to Mario after he defeats the second child of King Koopa, Morton Koopa, Jr. 3 Y Z You can stomp on your enemies using Goomba's shoe. Problem III: A Cryptogram To Provoke an International Incident qagaru rykb bj hjx aw ar wjiy lzhw qaey wqyyfaru labo zr yqyfozrb. rj izbbys ojl nsayrtqh zrt ygyr byifysyt aw boy dyzwb, an a mzr mzqq ab bozb, jry aw znnymbyt dh ygysh blabmo zrt usxrb.  fayssy yqqajbb bsxtyzx 4 1. What is the most common letter in the ciphertext? ______ 2. What double letters occur in the ciphertext? 3. Try your hand at solving the cryptogram. You may wish to keep a tally of your deciphered letters here: Ciphertext alphabet A B C D E F G H I J K L M N O P Q R S T U V W X Plaintext alphabet 4. Was the cipher alphabet generated using a shift ­cipher? How can you tell? 5. (To think about at home: how many letters would you have to have deciphered, minimum, in order to tell?) 6. (Imaginary) Bonus point: Why is the person that uttered this quote important? (Hint: Richard Nixon had a pretty negative opinion of him.) 5 Y Z ...
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This note was uploaded on 09/15/2011 for the course LIGN 17 taught by Professor Kehler during the Winter '08 term at UCSD.

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