The GCHQ (Government Communications Headquarters in the UK) has posted a code to solve on the "Can you find it?" website - to let you win a prize or even join them, but what is the answer?
The code is:
AWVLI QIQVT QOSQO ELGCV IIQWD LCUQE EOENN WWOAO
LTDNU QTGAW TSMDO QTLAO QSDCH PQQIQ DQQTQ OOTUD
BNIQH BHHTD UTEET FDUEA UMORE SQEQE MLTME TIREC
LICAI QATUN QRALT ENEIN RKG
To find the answer you have to visit different pages on the web and solve the code, just like Alan Turing did at Bletchley Park, when he invented the Colossus computer that the Nazis were using to send secured messages to one another. This page focuses on the code itself, rather than the pages on the web. The code is the enigma of the year!
Codes like this might have some false answers that still appear green when you enter them, therefore in order to be sure you've got the right answer, you should understand how the answer was arrived at. This page explains the kind of process you'd follow.
Answering the GCHQ Code starting AWVLI ...
The first thing you probably did is to try some of the obvious things ... reading the whole code backwards, taking the first letter of each word, etc. You probably noticed that there are an excessive number of Q's in the GCHQ code to, which isn't natural in English, particularly as there's not an excessive amount of U's. This suggests one of three things:
- It's a substitution cipher (letters are replaced with different letters).
- It's a transposition cipher (letters are reordered) and the Q's should be deleted at some point.
- It's a transposition cipher and the Q's are actually spaces, rather than letters
If we look at the frequency of letters (the information is presented twice, firstly in alphabetical order, then in terms of the most frequent letter), we have the following pattern:
Except for the Q, this is a very normal range, as E and T are the letters used the most often in the English language and J, X, Y and Z are all used rarely. This suggests that it's much more likely that in order to solve the code, you have to rearrange the letters (i.e. it's a transposition cipher), rather than substitute them for alternative letters.
There were previous examples of puzzles from GCHQ here - gchq.gov.uk/Challenges/Pages/Break-Some-Code-Puzzle-1.aspx (sorry the link's currently inactive) and while none of them start "AWVLI QIQVT QOSQO ..." (that would be too easy!) it seems likely that a similar pattern will be used, as that will reward people who have done some research on the QCHQ website.
So what's the answer to the code? Well ... I'll leave you to figure some of it out, however some things I spotted while I was solving it include:
If you remove the Q's then there's an anagram of 'To Solve' early on in the code. This may suggest a pattern for how the other letters are scrambled (unfortunately none I could apply effectively)
AWVLI IVT OSO ELGCV IIWD LCUE EOENN WWOAO
LTDNU TGAW TSMDO TLAO SDCH PI DT OOTUD
BNIH BHHTD UTEET FDUEA UMORE SEE MLTME TIREC
LICAI ATUN RALT ENEIN RKG
Removing the Q's from UMORE SQEQE gives "U MORE SEE"
The prizes are:
100 x Raspberry Pi and
5 x Google Nexus 7
I wondered if the number pi (3.14159265359...) perhaps to 100 decimal places is part of what you need to solve the code?
As it turned out, I was looking at overly complex solutions to the GCHQ "Can you find it" code and I read about some common code breaking techniques at http://www.thedavincigame.com/Code_breaking.html which gave me an idea as to the solution.
The Caeser Square (described in the above link) is a well known code breaking technique and means that you write the letters in a square and then transpose the rows and columns.
A give away that you should use the Caeser Square is that the total number of characters is a square number (9, 16, 25, 64, etc.) however going back to the original version with the 'Q's', I saw that it's 143 characters, which is 11 x 13 (or 13 x 11) and I wondered if a Caesar Rectangle might help? That started me off on the right track to question 1.
If the canyoufindit.co.uk GCHQ code is too tricky for you, then there's some quick riddles on the right-hand side that you might enjoy.