## Codebusters C

OrigamiPlanet
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### Re: Codebusters C

So states is coming up in PA, but I'm still very confused as to how the crib word is supposed to be utilized when doing cryptanalysis of a vigenere. I've looked online for a while now, but I keep getting the kasiski method, and while I do believe it is a very good idea to use, I still have no clue as to how the crib plays a part in all of this. Is it truly just a confirmation that you have been doing it correctly, or is there another method?
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pepperonipi
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### Re: Codebusters C

OrigamiPlanet wrote:So states is coming up in PA, but I'm still very confused as to how the crib word is supposed to be utilized when doing cryptanalysis of a vigenere. I've looked online for a while now, but I keep getting the kasiski method, and while I do believe it is a very good idea to use, I still have no clue as to how the crib plays a part in all of this. Is it truly just a confirmation that you have been doing it correctly, or is there another method?

Honestly, I had no idea what the Kasiski method was and after briefly looking at it, I can say that it doesn't seem like much fun.

For a Vigenère Cipher, just remember that (PT + KEY) mod 26 = CT, which means that CT - PT = KEY mod 26. This applies for all letters. So if you are given the first three words, then repeatedly use PT - CT = KEY, and you should start to find a pattern. Then, you can use your new-found key to solve the rest of the cipher.

For example, solve "Vvlw kg ksy W vsnjh xjsvi ewslgfv," where the first three words are "This is how":

First, T (=19) encrypts to V (=21), so we can find that KEY = 21 - 19 = 2, meaning that the first letter of our key is "C"
Second, H (=7) encrypts to V (=21), so we can find that KEY = 21 - 7 = 14, meaning that the second letter of our key is "O"
Repeating this process, we get:
CODECODEC

You can clearly see that the key is "CODE," which we can use to solve our cipher. Using this key gives us: "This is how I solve these ciphers."

I hope I am understanding your question right.
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will0416
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### Re: Codebusters C

Has anyone seen any particularly memorable varieties of encoding Baconian ciphers that have a decent chance of appearing on an official test (i.e. methods other than odd/even, vowel/consonant, letters from one word/letters from a different word)?
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Anomaly
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### Re: Codebusters C

will0416 wrote:Has anyone seen any particularly memorable varieties of encoding Baconian ciphers that have a decent chance of appearing on an official test (i.e. methods other than odd/even, vowel/consonant, letters from one word/letters from a different word)?

On our regionals test, we had something uses a bunch of symbols like !@#\$%^&*()
I never actually figured out what the pattern was though, it might have been all the symbols on the odd numbers of a keyboard / symbols on even numbers of keyboard
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will0416
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### Re: Codebusters C

Anomaly wrote:
will0416 wrote:Has anyone seen any particularly memorable varieties of encoding Baconian ciphers that have a decent chance of appearing on an official test (i.e. methods other than odd/even, vowel/consonant, letters from one word/letters from a different word)?

On our regionals test, we had something uses a bunch of symbols like !@#\$%^&*()
I never actually figured out what the pattern was though, it might have been all the symbols on the odd numbers of a keyboard / symbols on even numbers of keyboard

Oh that sounds pretty clever. I think I've also seen American currency vs. foreign currencies (maybe British) on a test before but there have been some Baconians that have just seemed impossible.
Mason ‘22
2019 Nats:
Code - 4
Mission - 4

AZ_120
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### Re: Codebusters C

For the timed question, I was wondering if you guys had people 2 or 3 people working on it or just 1 person. If it's more than 1, how do you work together on it?

GoldenKnight1
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### Re: Codebusters C

Anomaly wrote:
will0416 wrote:Has anyone seen any particularly memorable varieties of encoding Baconian ciphers that have a decent chance of appearing on an official test (i.e. methods other than odd/even, vowel/consonant, letters from one word/letters from a different word)?

On our regionals test, we had something uses a bunch of symbols like !@#\$%^&*()
I never actually figured out what the pattern was though, it might have been all the symbols on the odd numbers of a keyboard / symbols on even numbers of keyboard

Regionals was:
A: ><*
B: !&?

The one that I made that cause the most people trouble used the Cyrillic / Russian alphabet:
A: ИДЖ
B: ЛПЯ

eab2114
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### Re: Codebusters C

Does anyone have tips for working on patristocrats, beyond just looking at letter frequency and repeated letter chunks? I'm working on the North Carolina state test and not having much luck with it.

dragonfruit35
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### Re: Codebusters C

eab2114 wrote:Does anyone have tips for working on patristocrats, beyond just looking at letter frequency and repeated letter chunks? I'm working on the North Carolina state test and not having much luck with it.

Honestly, that's about all you can do, especially if there's no hint. We usually try plugging in the most common letters and seeing if anything jumps out and go from there.

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