• Replies 6 replies
  • Subscribers 30 subscribers
  • Views 358 views
  • Users 0 members are here
Options
Related
Hints and tips
  • To quote someone's message, first select/highlight the relevant text, and then use the Quote button that appears
  • To "mention" someone, type @ followed by the start of the forum name, and choose from the list; that person will get a notification of being mentioned

National Cipher Challenge

Trev

For anyone interested in learning about writing or decoding secret messages this is quite interesting:

www.cipherchallenge.org/

The ciphers used are mostly those in use prior to the Second World War.

There are tutorials on the website.

The target audience is A Level students and the prizes are for those registered through their school, however anyone can register and have a go at the ciphers (but you won't be eligible for the prizes).

It starts on Oct 9th, as I've had a go at it before I haven't decided yet if I'll do it again this year.

Edit: I just thought I'd add that you should be able to complete quite a few of the challenges by just using pen, paper and some online tools (the later challenges will need some simple computer programming)

  • I just thought I'd add a final post to this - it started today at 3pm.

    Challenge 1a and 1b aren't too difficult, so worth a try especially if you like doing a bit of computer programming.

    Although it has already started it isn't too late to have a go.

    The next challenge made up of 2a and 2b will begin next Thursday at 3pm (each challenge is more difficult that the previous one).

  • in reply to Stuart333

    It is a bit of a challenge but as it is aimed at A Level students at least the first few levels should be achievable by most people and if they made it too difficult it wouldn't encourage anyone into studying the subject.

    Something similar has been done: https://picrypt.org/ - it looks more like a historic rather than a modern cipher.

  • I took a quick look at this. I can imagine it could be fun, but also very frustrating.

    I was wondering whether you could have a way to index into Pi, say by using the length of the first sentence, then using that as a random number to give variable offsets for letter of the cipher.

  • I managed to get the bigram and trigram frequency analysis coding finished today.

    Since getting my diagnosis three weeks ago this is the first time I've been well enough to do any hobby activities, so hopefully I'll soon be back to doing some bits on my van.

    Doing the National Cipher Challenge shouldn't wear me out too much since as far as I can remember quite a lot of the challenges could be finished on the afternoon of the day they came out (one challenge a week) with only the last few challenges taking a bit longer.

  • I've decided this year I'll write my own code for statistical analysis of cipher text rather then using websites.

    Today I've done the code (in C) for reading some text from a file and displaying single letter frequency counts along with what one would expect in standard English next to it, with both listed from most common to least common (for example the letter E is most common and you would expect in most English text for 12.7% of the characters to be E).

    I've done enough for today, maybe tomorrow I'll start the code for bigram frequencies and trigram frequencies, ready for next week when the competition starts.

  • I've decided to have a go at it this year and have registered (you need to register as a teacher if you aren't in the correct age category and doing it through a school).

    For anyone who is thinking of having a go there are a couple of introductory ciphers to have a go at before the competition starts, the first one is just clicking on the direction you want a cipher wheel to rotate until the text becomes readable, the second one is a bit harder, but isn't too difficult and although I haven't clicked on the "tips" link I gather it gives you the answer.