Assignment Due 6 Sep

1.

The following text has been encoded using an additive cypher. Break the cypher and find the key. Show all your work, including guesses, errors, and dead ends. (This includes a frequency table if you make one, or part of one.)

Warning: this plaintext is unusually rich in ``t''s and ``o''s, in addition to ``e''s.

Hint: recall that we claimed in class that you only need to get one letter right in order to find the key.

KVSMOGKCLOQSXXSXQDYQODFOB
IDSBONYPCSDDSXQLIROBCSCDOBYXDROLKXU
KXNYPRKFSXQXYDRSXQDYNYYXMOYBDG
SMOCRORKNZOOZONSXDYDROLYYUROB
CSCDOBGKCBOKNSXQLEDSDRKNXYZSMD
EBOCYBMYXFOBCKDSYXCSXSDKXN
GRKDSCDROECOYPKLYYUDRYEQRDKVSMO
GSDRYEDZSMDEBOCYB
MYXFOBCKDSYX

2.

The following text has been encoded using the affine cypher with key [7, 1]. (That is, multiply by 7 and add 1 to encode.) Decypher the text. Show all your work, including guesses, errors, and dead ends.

LQTBRCBUKXJKJYJWTKELUXTBRFHUKKELUZ
BQKEJKELUXDTBRCBUKXJK
KEHKTBRCBUKFHUKBDVHWFLGCJ

3.

The following text has been encoded using an affine cypher. Break the cypher and find the key. Show all your work, including guesses, errors, and dead ends. (This includes a frequency table if you make one, or part of one.)

Hint: to find the key, look at the cyphertext letters corresponding to plaintext letters that are early in the alphabet, such as ``a'' and ``e''.

FWWOTRWOZLOXIZCFPDMXRZBCTSWXW
OZFTMFSUPFNZEIVTSJUXLSBCXSOZM
ROZJFGZFITWWIZRPMZFNOFIEXEEMT
JOWFSUOFIEXEFSJZMFSUWMTZUWX
KZFWWOZNXEEFSUEXBSUOZMRZIEIV
TSJXSWOZKFSDLTWOOZMOZFUTSWOZ
IFCXEOZMRTRWZMLOXLFRJZSWIVKMB
ROTSJFLFVRXNZUZFUIZFGZRWOFWOFU
EIBWWZMZUUXLSEMXNWOZWMZZRBCXSOZMEFPZ

About this document ...

Assignment Due 6 Sep

This document was generated using the LaTeX2HTML translator Version 97.1 (release) (July 13th, 1997)

Copyright © 1993, 1994, 1995, 1996, 1997, Nikos Drakos, Computer Based Learning Unit, University of Leeds.

The command line arguments were:
latex2html -link 0 -split +0 ciphers1.

The translation was initiated by Joshua Holden on 9/3/2000