NKEVI RHCTO GBALU PDMFS ZQWXYwhich produced the plaintext:
THISSTAGEISNUMBERSIXANDITISAPLAYFAIRCIPHERSTOPTHEFOLLOW INGSTAGEISNUMBERSEVENWITHINTHECONTEXTOFTHISCOMPETITIONA NDITISENCRYPTEDACXCORDINGTOANADFGVXTYPECIPHERSTOPWHENYO UATTEMPTXTOCRYPTANALYSESTAGESEVENYOUWILLSEXETHATITISMOR ECOMPLICATEDTHANASTRAIGHTFORWARDADFGVXCIPHERSTOPUNFORTU NATELYICANXNOTGIVEYOUANYMORECLUESSTOPNEWPARAGRAPHINTERM SOFTHISXSTAGETHESHIBBOLETHTHATYOUSHOULDTAKENOTEOFISMOLY BDENUMNEWPARAGRAPHYOUWILXLPROBABLYHAVENOTICEDBYNOWTHATE ACHSTAGEISINADIFFERENTCIPHERANDISUSUALLYINANAPPROPRIATE LANGUAGESTOPSOTHEVIGENERESTAGEWASINFRENCHANDTHISPLAYFAI RSTAGEISINENGLISHSTOPIFTHEPATXTERNPERSISTSTHENTHENEXTST AGEWILXLBEINGERMANSTOPBUTDOESTHEPATTERNPERSISTQUESTIONM ARKQIf we format the text and replace the formatting words present in the plaintext we get the following message.
This stage is number six and it is a Playfair cipher. The following stage is number seven within the context of this competition and it is encrypted according to an ADFGVX type cipher. When you attempt to cryptanalyse stage seven you will see that it is more complicated than a straightforward ADFGVX cipher. Unfortunately I cannot give you any more clues.The codeword for this stage is thus MOLYBDENUM. We also realize that the key was not created at random. If rotate the columns of the key one step to the left we obtain
In terms of this stage the shibboleth that you should take note of is molybdenum.
You will probably have noticed by now that each stage is in a different cipher and is usually in an appropriate language. So the Vigenere stage was in French and this Playfair stage is in English. If the pattern persists then the next stage will be in German. But does the pattern persist?
KEVIN HCTOR BALUG DMFSP QWXYZWe guessed that the first two rows emerge from ``Kevin Hector'' and searched for that name to find that it was the name of a front football player in Derby FC during the 1970s. We could not make out the origin of the rest of the key, however. Simon later hinted that the name of the coach of Derby at that time, ``Brian Clough,'' was used for the third row. The fourth row is still a mystery.