7937 /www/nrich/html/content/id/7937/ 1 2011-12-21T11:16:43 <mdoxml version="1.0"><br></br> <p>This is the fourth part of the <a href="/7934">Secondary Cipher Challenge</a>.</p> <p> </p> <h3>Part 4</h3> <div class="pdm"> <p style="text-align: center;">ctutithidrosaoiewblnssyulcceeseiheksnpherigefive</p> <p> </p> </div> <p> </p> <p>You can use the <a href="http://nrich.maths.org/7983">Cipher Challenge Toolkit</a> to help you decipher it.  </p> <br></br> <p><strong>Once you've decrypted this message, you should have a keyword.</strong></p> <p>You can access Part 5 of the Cipher Challenge at http://nrich.maths.org/???<br></br> by replacing the ??? with the keyword.</p> <br></br></mdoxml> <mdoxml version="1.0"><pre> Challengefiveissubstitutioncipherkeywordischeese </pre> <p> </p> <pre> c h a l l e n g t i o n c i p e u d i s c h h f t r e s e e e i i o w y e k r v t s b u s s i e </pre></mdoxml> 2 4 0 0 1 1 0 Here is the fourth part of a six-part challenge. Can you get to the end and crack the final message?