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+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Breaking caesar ciphers</title>
+    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
+    <style type="text/css">
+      /* Slideshow styles */
+      body {
+        font-size: 20px;
+      }
+      h1, h2, h3 {
+        font-weight: 400;
+        margin-bottom: 0;
+      }
+      h1 { font-size: 3em; }
+      h2 { font-size: 2em; }
+      h3 { font-size: 1.6em; }
+      a, a > code {
+        text-decoration: none;
+      }
+      code {
+        -moz-border-radius: 5px;
+        -web-border-radius: 5px;
+        background: #e7e8e2;
+        border-radius: 5px;
+        font-size: 16px;
+      }
+      .plaintext {
+        background: #272822;
+        color: #80ff80;
+        text-shadow: 0 0 20px #333;
+        padding: 2px 5px;
+      }
+      .ciphertext {
+        background: #272822;
+        color: #ff6666;
+        text-shadow: 0 0 20px #333;
+        padding: 2px 5px;
+      }
+    </style>
+  </head>
+  <body>
+    <textarea id="source">
+
+# Breaking caesar ciphers
+
+![centre-aligned Caesar wheel](caesarwheel1.gif)
+
+---
+
+# Brute force
+
+How many keys to try?
+
+## Basic idea
+
+```
+for each key:
+    decipher with this key
+    how close is it to English?
+    remember the best key
+```
+
+What steps do we know how to do?
+
+---
+# How close is it to English?
+
+What does English look like?
+* We need a model of English.
+
+How do we define "closeness"?
+
+
+    </textarea>
+    <script src="http://gnab.github.io/remark/downloads/remark-0.6.0.min.js" type="text/javascript">
+    </script>
+    <script type="text/javascript">
+      var slideshow = remark.create();
+    </script>
+  </body>
+</html>
+\ No newline at end of file