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November 21, 2005
Think cryptic
The challenge is double encrypted. The old European cipher is French (now does the V help?) and has been combined with a "twist" i.e., some sort of transposition cipher. I can't give much more than that away. Good luck,
Posted by Harry at November 21, 2005 05:07 PM
Comments
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Harry, When the honours board be updated?
Posted by: Mike at November 24, 2005 01:04 PM
When I first saw the Latin five thing I was thinking of Latin squares and started off wondering if the cipher was 3 3x3 grids so that the combinations of 0s, 1s and 2s would tell you which square it was. I hoped the five bit would become obvious later. I was quite relieved when someone pointed out that the 2s were just delineators for the letters. I had a spreadsheet from last year to help with the Vigenere cipher and the crib start was a great help - even without knowing how long the keyword was.
Posted by: Jonathan at November 24, 2005 12:16 PM
Wasn't this 6B more like the 7B ('reflect...') from last year, i.e. transposing the letters like in excel?
Posted by: Simon at November 24, 2005 11:21 AM
I give up, I'm useless. I got past the Vigenère, but couldn't handle the transposition. Unless I got the wrong Vigenère translation...it began with CAYU, is this right?
Never mind.
Harry, can we miss one cipher out but still be in the running and carry on with the next one?
Posted by: I'm Lost at November 23, 2005 11:13 PM
Still stuck? As you may have gathered, the keyword is 11 letters long, appears in 6A and is more like a compilation of 3 words, beginnning fi... The transposition is basically swapping rows and columns. Hope that helps ;)
Posted by: cecil at November 23, 2005 10:49 PM
i have finally had time to do the challenge and it only took me about 40 minutes overall, with programs too. maybe i will try the next one before the last night.....thanks for all the clues, they really heled me
Posted by: chloe at November 23, 2005 08:15 PM
HELP!!!! Four hours to go and i've got no where!
Posted by: Cara at November 23, 2005 07:45 PM
ok.i'm going to crack this code or die trying... and at the minute, it looks like the second option is more likely.
Posted by: lara at November 23, 2005 06:39 PM
ok. i am really starting to panic now. i have got it in the grid, i know the key word, have written it across the top... but i can't see any message. please help.
Posted by: lara at November 23, 2005 06:33 PM
Everyone complaining about how hard this challenge was, it is the same method as 8A last year, so it cn't be that hard if it was an A.
Posted by: Ruth at November 23, 2005 06:25 PM
Wait, it was Metals wasn't it!
So what are the timing intervals for the next round?
Posted by: Jason at November 23, 2005 05:53 PM
Jason, saying good luck was merely meant as a jesture of goodwill. I think that you will find I have been revising hard for it and guessing will not (probably) come into it.
Posted by: Steve Lmaerton at November 23, 2005 05:49 PM
Oh yes, you're right John. I should have looked at least a few seconds for the pattern. And how obvious it is! Silly me.
Well, if you haven't done the challenge by now, you must have been seriously unprepared for all the ciphers. Vigenère is mentioned in the teacher's pack, and that is what this challenge is, combined with a very simple transposition.
So how does luck help with the Science modules? Unless of course you are going to guess the answers. The syllabus tells you everything you need to know :) I still don't understand why we had to learn about the blast furnace for Earth Materials... How many are left in this country?
Posted by: Jason at November 23, 2005 05:27 PM
harry... not long left now- can we have a clue please?? a big clue?? *looks hopeful*
[What do you want. If you can do Babbage Kasiski you should be able to do this. If you look carefully through all teh comments you will find that someone mentioned that 32 is congruent to -1 modulo the length of the keyword for the Vigenere, so that should help (it means that 33 is divisible by the length of the keyword hint hint!] If you do get that far then for goodness sake leave the text in its 32 by 32 grid and just look hard. I can't give more help than that. Harry]
Posted by: Katie at November 23, 2005 04:25 PM
Just to say good luck to all of the people with Science GCSE exam modules tomorrow!
[Here, here. Harry]
Posted by: Steve Lamerton at November 23, 2005 03:55 PM
Don't worry about the Five bit for the moment, just think Latin. I asked my friend about it and he said something about it that I thought was really simple and that it was impossible that it was that easy. But then i realised that it was TWO ciphers and one of them was what my friend told me. Have you noticed that 1024 is 32 by 32?
Posted by: Tiddy at November 23, 2005 01:05 PM
Jason, have another look at that keyword done the "wrong" way: it's not rubbish, it's just the "right" one permuted.
This works because the numbers 32 and 11 are significant in this puzzle, and because 32 is 1 less than a multiple of 11.
If the numbers were 34 and 11 (1 more than a multiple of 11), the keywords would be the same, "right" and "wrong" ways around.
Posted by: John at November 22, 2005 09:40 PM
the keyword is a phrase that appears once, quite early on in 6A. It has been mentioned several times on the comments by various people.
Posted by: Ruth at November 22, 2005 09:38 PM
The Latin Five was meant to be a V (for Vigenere) as the Romans, who spoke Latin, used a V to give the number 5. Bit obscure, I agree- more effective as an amusing thing after you've solved the cipher and not as a clue!
Posted by: Jess at November 22, 2005 09:28 PM
help with keyword could have been better than telling us the cipher. dont tell us but give a clue please!
Posted by: freaks at November 22, 2005 08:50 PM
i cracked the code without a keyword or using vignere, i still dont understand latin 5, and im not sure how i worked it out, but its in blocks of 11! hope that gets let tru, mite not but it is tuesday after all. can any1 tel me the meaning of "latin five" because i cant c how it was ment to help, cribs r useful tho! p.s. umm, wot wos my ps again...
Posted by: Insane (FHS) at November 22, 2005 08:23 PM
Ah no! 8:05, damn computer! If you haven't yet solved it yet, I hope Harry will let these clues through. You only need to find the length of the keyword - and its not the length of a short word, of say 5/6 letters. Try different keyword lengths, stick with it for a while and see if you can makes sense of it. The 32X32 grid comes in handy here - this has nothing to do with the keyword though! Hope this helps
Posted by: Stephen Harris at November 22, 2005 08:09 PM
Wow, it does actually work both ways! All down to the symmetry of the transposition. However, one way is much, much easier than the other. The longest repetition the right way is 17 letters long, compared to the 4 of the wrong way. Also, there is no keyword the wrong way, just rubbish.
I had a look at the Kasiski applet (by Tom Linton). Compared to my keyword length finder, it isn't so brilliant. All it does is find repetitions of 3 letters, when what you really want is the long sequences, which are much more significant. My program gives each keyword length a score based on a formula of my own creation, making the keyword length obvious with vigenère on its own, and even quite clear if you are doing things the wrong way in this challenge. If you can program, give it a try! By the way, this is still the Kasiski test, but it represents the data in a more useful way.
WARNING: there are some inaccuracies in Alex's description of the Fialka machine. I won't tell you what they are though. Research for yourself! If you have done 6B, you will already know something about Challenge 7.
Posted by: Jason at November 22, 2005 06:55 PM
I DON'T GET THIS!!!! how am i meant to do a frequency analysis on something when the frequency of loads of letters are soooo similar and because of the twist, i won't be able to deduct between those letters. help. and how does this vigeniere cipher work anyway. i've looked for information on it, but none of its really particularly useful.
[If there is a Vigenere cipher you need to know its periodicity (how often the sequence repeats) Look for repeated pairs or triples and see how big the gaps are between the repeats. The period of the cipher is then a factor of the gap length. You have to be careful because some of the repeats could be accidents, but overall this gives a good clue to the length of the keyword. This is what is known as the Babbage Kasiski method. Say the period turns out to be 7. Do frequency analysis on the set of letters you get fin positions 1, 8, 15 and so on to work out which Caesar shift has been used for them. Then repeat for the letters in position 2, 9, 16, ... and then for those in positions 3, 10, 17, ... and so on. That should get you through the Vigenere stage. What you get won;t look right because of the twist, but if you look at it the right way ...... Harry]
Posted by: lara at November 22, 2005 06:18 PM
ok, i am utterly useless. my team have deserted me and i really need help. i tried cribs, double/triple letter thing and got nowhere. any other helpful advice would be much appreciated.
Posted by: laura at November 22, 2005 05:59 PM
that's a great help... I knew that about a week ago but still can't get over the last hurdle... kasiski test doesn't seem to work, which is annoying... my usual trusty applet is letting me down :(
Posted by: cecil at November 22, 2005 07:12 AM
Look at what Katie said Laura!
(I know what you mean about the backlog of homework, I think cipher challengers should be excused all homework while the Challenge runs! It's not our fault we have no time anymore!)
Posted by: Jess at November 22, 2005 07:11 AM
You can do the Vignere first, as it makes the transposition easier to spot.
To figure out the length of the keyword, look for repeated sequences of letters, and count up how many letters there are between the repeats, the length of the keyword will be a factor of this.
You do not neeed to know the keyword itself as it will be revealed as you break each individual line of the Vignere.
Posted by: cipherbloke at November 22, 2005 06:33 AM
so which one is first?
the transposition or the vigenere? because it does make all the difference.
please, someone take pity (i am struggling under a backlog of h/w from relentless teachers)
Posted by: laura at November 21, 2005 10:53 PM
Ohh! I get it now. I solved the cipher ages ago, but I've only just worked out the "Latin Five" clue. Very subtle, Harry!
Posted by: Clever Code Cracker at November 21, 2005 09:53 PM
Have i got totally the wrong idea here, or is it a vignere then a transposition, or the other way round?? we didnt struggle this much with last years challenges- why is it so difficult?! :-(
[That's the idea! Harry]
Posted by: Katie at November 21, 2005 09:43 PM
PLEASE let there NOT be a Fialka cipher in Challenge 7! Apart from the fact that there are several different types (M-100, M-105, M-125-MN, M-125-3MN, M-125-3MP3 and M-125-3MP2), it is EXTREMELY complex: it has a card reader (which acts like the Enigma plugboard), there are TEN rotors which rotate in different directions (and two sets of rotors making TWENTY in total), the second set of rotors can have their wiring adjusted, the rotors have random blocking pin locations and there are 30 letters to a rotor!
Just one more word: how!?
Posted by: Alex at November 21, 2005 09:32 PM
Hay Laura
I have been looking at Vigenere all week but I too cannot get the keyword. Harry did say previously that a keyword was not necessary, so now what? I have tried so many of the words from part A as a keyword and still get rubbish. I am now on the point of giving this one up as a bad job. Hope they give an explanation on Thursday on how it was done as they are not giving any more hints. Still there is always 7A to come.
[You can use frequency analysis once you have figured out the length of the keyword. This you do by searching for repeated pairs or triples. You can look this up in SImon Singh's book if you don;t know how. Harry]
Posted by: richard at November 21, 2005 09:11 PM
Laura, have you thought at all about cribs?
Posted by: Jess at November 21, 2005 07:51 PM
I can't believe it! At least 2/3rds of our team are out with illness, one with major flu! Just hoping we're back on form for thursday!
Posted by: piman at November 21, 2005 06:15 PM
heya, i knew it was vigenere, but the keyword is killing me.
any clues as to the length or the first letter of something?
please?
Posted by: laura at November 21, 2005 05:41 PM
Just out of interest, having not read any of Darren Brown is the cipher that people refer to the same as this one in the transposition stage?
Posted by: Stephen Harris at November 21, 2005 05:21 PM