slides/caesar-break.html

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   4     <title>Breaking caesar ciphers</title>
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  44
  45 # Breaking caesar ciphers
  46
  47 ![centre-aligned Caesar wheel](caesarwheel1.gif)
  48
  49 ---
  50
  51 # Brute force
  52
  53 How many keys to try?
  54
  55 ## Basic idea
  56
  57 ```
  58 for each key:
  59     decipher with this key
  60     how close is it to English?
  61     remember the best key
  62 ```
  63
  64 What steps do we know how to do?
  65
  66 ---
  67 # How close is it to English?
  68
  69 What does English look like?
  70 * We need a model of English.
  71
  72 How do we define "closeness"?
  73
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