QUWFAIUQ KMWUV MK YMB WM VXRJAW WYU BUR OFCUV FKQ TMRXVW IAKSAKC FTU FZFAIFRIU FW WYU XTI FRMZU XKQUT BUR RFVUQ FVVUVVJUKWV OFTWAEXIFT EFTU VYMXIQ RU WFSUK MZUT WYU AKEMTOMTFWAMK MN IAKSV FKQ WUVWAKC MN WYU VWTXEWXTU MKEU WYU QMEXJUKQV YFZU RUUK OIFEUQ MK WYU VAWU CXAQUIAKUV FTU QAVEXVVUQ MK WYU VAWU FKQ F OUTAMQ VYMXIQ RU FIIMBUQ NMT WYAV FVOUEW MN WYU UDEUTEAVU JMQANAEFWAMK MN WYUVU AV KMW OMVVARIU FNWUT WYU QUFQIAKU
The first thing you notice is that you can't read it. In fact, you can't even pronounce it. This hints at the way you solve it. The reason you can't pronounce the coded message is that the letters you see are in the wrong places relative to each other, and the are too many of certain letters and not enough of others. QUWFAIUQ is unpronounceable because you never get W and F next to each other, or UQ in that order, so you have never had to work out a way to pronounce those syllables.
For example, the most common letter in English is E. So you expect lots of Es in the paragraph, which isn't the case. This is because E has been coded as a different letter, and you don't know which one. But can you work it out? If E is the most common letter, then if it is coded, it's code-letter should be the most common code-letter. Or at least one of the most common. And the same goes for T and A, the next most common letters in English. A look at the coded text shows that the six most common letters are:
U: 52 W: 32 V: 29 M: 27 F: 27 A: 24
We can guess straight away that U=e, and that two of W, V, M, F and A are a and t. To help decide which, we can notice that the three-letter word WYU appears nine times, and since U=e, it ends in e. This is probably the word the, in which case W must equal t which fits in with W being the second most common letter in the code text. And so Y is h. Then notice WYUVU in the last line which could be these or there. And WYAV which could be than or this or thus or thug.
FKQ appears three times, and can be guessed to be and. This fits in with F being common and appearing on its own is the second-to-last line; it must be a. So K=n and Q=d. This also works because five words end in UQ (ed) which makes sense since many words in English end in -ed.
WYAV can't be than since a=F, and it is unlikely to be thug since V is the third most common letter and is very unlikely to be g. But it could be this or thus, making V=s. This also works because there are four occurrences of VV, or double s, which is fairly common in English. Certainly it can't be g since gg is far to uncommon to appear 4 times in one paragraph. Another thing we can notice is that there are many two-letter words containing M, such as MK and WM. M is therefore likely to be a vowel, and can't be a or e since these have been assigned already. It won't be u since it is too common, and can't be i since i doesn't come at the end of two-letter words, so must be o. That leaves i to be equal to A, from the guess of WYAV=this from earlier, and the fact that A is one of the few common letter yet to be assigned, and appears in the right place in many words. So so far we have:
detaiIed notes on hoB to sXRJit the BeR OaCes and ToRXst IinSinC aTe aZaiIaRIe at the XTI aRoZe XndeT BeR Rased assessJents OaTtiEXIaT EaTe shoXId Re taSen oZeT the inEoTOoTation oN IinSs and testinC oN the stTXEtXTe onEe the doEXJends haZe been OIaEed on the site CXideIines aTe disEXssed on the site and a OeTiod shoXId Re aIIoBed NoT this asOeEt oN the eDEeTEise JodiNiEation oN these is not OossiRIe aNteT the deadIine
From here it is getting progressively easier and easier to fill in the rest of the letters, and soon we can show the original text to have been the first paragraph form the sheet I was given telling me about this assignment:
detailed notes on how to submit the web pages and robust linking are available at the url above under web based assessments particular care should be taken over the incorporation of links and testing of the structure once the documents have been placed on the site guidelines are discussed on the site and a period should be allowed for this aspect of the exercise modification of these is not possible after the deadline
And the key used by the encryptor is:
a b c d e f g h i j k l m n o p d r s t u v w x y z F R E Q U N C Y A L S I J K M O P T V W X Z B D G H
Which is an example of the codeword key - using the phrase FREQUENCY ANALYSIS and adding the rest of the alphabet afterwards.