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October 24, 2005
Computers and stuff
As I said earler, there is a great discussion of programming languages going on here, but I just wanted to remark that, while computers certainly can speed up code breaking, most of the ciphers we use in the competition don't need clever programmes to break them. You could tackle them using pencil and paper if you had to, though you can speed up the process by using a word processor or spreadsheet. The last challenge in the competition really would be tricky to tackle that way, but by the time we are done giving hints, clues and extra info you should even be able to crack that one without writing any code, so don't despair if you don't know how to get started.
On the other hand you shouldn't be put off trying something new. Even writing an Excel macro to replace the cipher alphabet with the plaintext alphabet can give you a real buzz when it works, and of you have time to play with a perl script or a simple visual basic programme it may give you confidence to try something more adventurous next time.
Posted by Harry at October 24, 2005 10:57 PM
Comments
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i agree with cecil at the bottom here that programmes are very helpful but there is a certain feeling when its cracked completely by hand, was using a programme for the monoalphabetic ciphers (checking the frequency analysis and finding the closest match to english by random tweaking of the keys) but i always do them myself afterwards just to get the feeling of cracking them myself
Much nicer i think to do it like the real wartime people would
Martyn from paston college, norfolk
Posted by: Martyn Compton at October 28, 2005 11:51 AM
at what time today will part 5 be published?
[4pm as usual, Harry]
Posted by: alex at October 27, 2005 01:08 PM
Jaccy, since the challenge is over, this probably won't help but anyway:
---- = ch
This has been treated as both a single letter (in terms of morse code) and a double letter (the c and h get moved seperately in the transposition). I presume this is to make it easier because you can not know what ---- means and still transpose (two) blanks from the lines with only four characters. You can then guess from context what the letters are.
Hope that helps.
cecil
Posted by: cecil at October 27, 2005 11:58 AM
There's an error in the schedule for the challenges. It says challenge 5 ends on Sunday 09th of October 2005 23:59 instead of Wednesday 09th of November 2005 23:59
[Whoops, thanks, harry]
Posted by: Ruth at October 27, 2005 11:47 AM
Just something to follow up on my question at the beginning of the competition. If we do get a Playfair, what do we do about the I/J character?
Posted by: Feng at October 27, 2005 11:21 AM
I had a little trouble with the middle of challenge 4B and I was wondering in what way was it different to the rest?
Posted by: Jaccy at October 27, 2005 12:50 AM
hi harry
can we still access last year's ciphers or are they no longer available? Also, last year, you gave us some links, will we be given any links this year to help us a little? Thanks.
Posted by: Jaccy at October 26, 2005 09:30 PM
Harry,
Last year in the rules it had a part about how characters such as ü, è, ä etc... should be replaced with u, e, a respectively. This year there's nothing in the rules about that, does this mean we should discard any of these characters, because if we discard them and you expect us to convert them, or vice versa, then our submission would be incorrect.
Posted by: tom at October 26, 2005 11:19 AM
For competitions 2 & 3 (Egypt and Alchemists), I did Freq. Anal. using Find and Replace in Word. Now I've managed to use the functions in Excel to do it for me, but it was really fun working out what I had to write in what order to get the instructions to work.
I also use find and replace to change to substitution cipher into plain text.
Posted by: Clever Code Cracker at October 26, 2005 09:54 AM
Thanks for the comments pages Harry.
Posted by: at October 25, 2005 12:15 PM
I was just gonna say that I think the way the challenges are designed means that programming isn't really needed. I used excel for the double playfair (no macros needed) and basically did the Solitaire by hand, and need only write a simple program for some simple number-crunching (I wrote this in VB, but only because it was available and we have a few tutorials on it already, it probably could have been done by any free, widely-available programming language as well). In terms of the way challenges were designed, I don't think it is a coincidence that the two jokers appeared in the first part of the key...
The first challenge I did (1A last year) we did frequency analysis by hand. There were about ten of us and we each counted the number of letters in each line of the text. Oh what a long way I've come. As Harry, said the sheer satisfaction of a working program (mine for a cesar shift, admittedly) was all worth the effort.
Posted by: cecil at October 25, 2005 08:58 AM