7708 /www/nrich/html/content/id/7708/ 1 2011-10-24T11:57:45 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"> <p>ThsehuyvbshwtihepueaaieieeiqelisrrbnrnnloukaTeieigotelneeshdsItafhxbosyteiatoscetefuwctnC sbqhmoatsoietapvuaencherpcheriarseoeddhhisoorasmmtsfensabuecaibeooricrasntggicfrwqisbhu eehnhataupqlamrTtanr</p> </mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><p>Have you managed to solve the entire <a href="http://nrich.maths.org/7081">Stage 5 Cipher Challenge</a>? Solutions are now closed, but perhaps you want to take up the full challenge.</p> <br></br> Successful solvers of this part were<br></br> <br></br> Patrick from Woodbridge School, England<br></br> An Anonymous Solver from Somewhere in the US<br></br> Joseph from Hong Kong <p> </p> <p>The solution was:<br></br> <br></br> The keyword for the last cipher was pi. The technique used in this cipher is a Caesar square. It&#39;s probably a bit obvious having a square number of characters in the message. The next one might well be a combination of the techniques used so far.</p> <p> </p></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><p>This challenge cipher forms part of a very difficult <a href="http://nrich.maths.org/7081">sequence of ciphers</a> suitable for keen groups or individuals, maths clubs and very optional homework challenges. Don&#39;t try this in the classroom!</p></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><p>This is the fifth of our <a href="https://nrich.maths.org/7081">challenge ciphers</a>.</p> <p>We recommend that you attempt them in order, as the solution of each challenge gives a small (and necessary!) hint for the next challenge.</p></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"> <p> </p> <div>The keyword for the last cipher was pi. The technique used in this cipher is a Caesar square. It&#39;s probably a bit obvious having a square number of characters in the message. The next one might well be a combination of the techniques used so far. </div> <div> </div> </mdoxml> 2 5 0 0 0 0 1 Fifth challenge cipher Decision Mathematics and Combinatorics Combinatorics Decision Mathematics and Combinatorics Algorithms Applications Codes and cryptography