Cipher Clock

[Tommystorm]

Could someone please explain the deadlines dates to me? It seems like some of the dates
are overlapping, is it a typo?
[Actually just realised it is not a typo, it is correct as stated. 3 in the afternoon on Thursday to 11 in the evening same day, then 11 Thursday evening to lunchtime Friday. Then lunchtime Friday to 11 pm Friday etc. Apologies again, Harry]

Start	                End	                Points
10/12/2020 3:00pm	10/12/2020 11:00pm	540
10/12/2020 11:00pm	11/12/2020 12:00pm	535
11/12/2020 12:00pm	11/12/2020 11:00pm	530

[Madness]

@Teymour_aldridge, It’s not clear to me how your mating scheme (PBX) works. Can you provide an example? Thanks.

[Madness]

Here’s some info on actual existing physical cipher clocks:
Wheatstone: http://incoherency.co.uk/blog/stories/wheatstone-cryptograph.html
Wadsworth: https://www.nsa.gov/Portals/70/documents/news-features/declassified-documents/friedman-documents/patent-equipment/FOLDER_515/41788379082740.pdf
Urkryptografen: http://www.jproc.ca/crypto/crypto_watch.html

[Xmask]

I’m getting the unnerving feeling that Madness managed to sort this one out really quickly and was done before even posting here. sigh

[I think you will be amazed when you hear how long it took him. Harry]

[67105112104101114]

@Xmask, if you are still having issues with ‘#’ then a solution is to put the ciphertext into word and then use find and replace to replace # with a different character which it doesn’t have an issue with

[Teymour_aldridge]

The crib is essential.

[Teymour_aldridge]

There’s an interesting paper about how to crack them without any knowledge of the alphabet (or a crib).

I might write a small blog post (+ some code) about this, if anyone would be interested. It will probably have to be released in January though, so as not to disrupt the competition (unless Harry has any thoughts on releasing it earlier).

[F6exb]

And somebody wrote a paper about the way to break the cryptograph a few months ago.

[Kford-academy]

Is anyone having trouble working out the key? If so… (Harry, I leave it to you to post the following hint whenever you like. It is not up to me to decide when to post hints!)

Only certain diagraphs may show…

[67105112104101114]

Up to Harry as to whether or not to release this comment, but the crib is not necessarily essential.

[Kford-academy]

@Teymour_aldridge, I didn’t use the crib whatsoever!

[Madness]

There is another way to break 7B by looking at which letters follow which other letters. If Harry lets this comment
get through, then maybe you can figure out how it works.

[Xmask]

(i’m betting on him finishing in 20 minutes)

[…] … and pretty much all of that’s gonna be edited out I bet [Yep, Harry]

[Xantali]

We FINALLY managed to make a functioning decrypter thing! I’m so proud of us 🙂 We’d never done anything quite like that before so yeah, took a while but perseverance eventually worked. Just gotta find the key…kinda stressed about that but ya know, hopefully we’ll make it in time for today’s deadline.

[Xantali]

I was just wondering about that hidden message in one of the ciphers from a previous week…and like (dunno if you’ll tell me, Harry, or this is asking for too much help), is NT just meaning number theory or something? Cos I’ve been trying to incorporate it in the keyword or something…but maybe I’m overthinking it and it isn’t necessary to crack 7B?

[Author]

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