Codebusters C

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dragonfruit35
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Re: Codebusters C

Postby dragonfruit35 » January 25th, 2019, 6:38 am

jimmy-bond wrote:I got my test back and realized that they encoded it using a 24-letter alphabet instead of 26 and I am now kicking myself, because the left symbols were A and right symbols were B, which is what I tried initially.


Oh nooooo :cry:

PS: I think this might help you :)

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Re: Codebusters C

Postby jimmy-bond » January 25th, 2019, 9:23 am

dragonfruit35 wrote:
jimmy-bond wrote:I got my test back and realized that they encoded it using a 24-letter alphabet instead of 26 and I am now kicking myself, because the left symbols were A and right symbols were B, which is what I tried initially.


Oh nooooo :cry:

PS: I think this might help you :)

Thank you. I didn't know that. That might be the reason I mess up on most practice tests.
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Re: Codebusters C

Postby Carrot » January 30th, 2019, 8:44 am

For solving the timed question, can you get it checked when you still have 1 or 2 errors (as often I can't think of the last word with two missing letters in it) or do you have to fully solve the problem?

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Re: Codebusters C

Postby Riptide » January 30th, 2019, 10:13 am

Carrot wrote:For solving the timed question, can you get it checked when you still have 1 or 2 errors (as often I can't think of the last word with two missing letters in it) or do you have to fully solve the problem?

Yes you can have it checked with up to 2 errors.
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Re: Codebusters C

Postby mpnobivucyxtz » January 31st, 2019, 6:33 am

Is there a standard format for this event? Last year's nationals test provided frequency tables and the Vigenere table as well, but some invitationals I've seen provide neither. What can I expect from regionals and states?

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Re: Codebusters C

Postby Longivitis » January 31st, 2019, 7:23 am

mpnobivucyxtz wrote:Is there a standard format for this event? Last year's nationals test provided frequency tables and the Vigenere table as well, but some invitationals I've seen provide neither. What can I expect from regionals and states?


Ideally they should provide the Vigenere table, letters to numbers (A = 0, B = 1), Baconian table, modulo inverse (rarely), and texts for running key ciphers. They should also have frequency percentages for English and Spanish as well.
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Re: Codebusters C

Postby jimmy-bond » January 31st, 2019, 8:10 am

Longivitis wrote:
mpnobivucyxtz wrote:Is there a standard format for this event? Last year's nationals test provided frequency tables and the Vigenere table as well, but some invitationals I've seen provide neither. What can I expect from regionals and states?


Ideally they should provide the Vigenere table, letters to numbers (A = 0, B = 1), Baconian table, modulo inverse (rarely), and texts for running key ciphers. They should also have frequency percentages for English and Spanish as well.

And unideally, you get nothing and have to do Vigenere the long way, write out the letters to numbers, manually calculate Baconian, and memorize the modulo inverse table as well as frequencies of English and Spanish letters. However this normally only comes up with student-made tests so I wouldn't worry about it at a higher level.
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Re: Codebusters C

Postby Riptide » January 31st, 2019, 9:58 am

jimmy-bond wrote:
Longivitis wrote:
mpnobivucyxtz wrote:Is there a standard format for this event? Last year's nationals test provided frequency tables and the Vigenere table as well, but some invitationals I've seen provide neither. What can I expect from regionals and states?


Ideally they should provide the Vigenere table, letters to numbers (A = 0, B = 1), Baconian table, modulo inverse (rarely), and texts for running key ciphers. They should also have frequency percentages for English and Spanish as well.

And unideally, you get nothing and have to do Vigenere the long way, write out the letters to numbers, manually calculate Baconian, and memorize the modulo inverse table as well as frequencies of English and Spanish letters. However this normally only comes up with student-made tests so I wouldn't worry about it at a higher level.

I don’t see any reason why event supervisors should provide a baconion table, modulo inverse, or even a letters to numbers table. Kind of takes away any skill gap this event could have for the non mono alphabetic ciphers. I do all the Vigenere by hand because it’s faster for me, but I can understand providing a table for that.
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Re: Codebusters C

Postby mpnobivucyxtz » January 31st, 2019, 10:27 am

jimmy-bond wrote:
Longivitis wrote:
mpnobivucyxtz wrote:Is there a standard format for this event? Last year's nationals test provided frequency tables and the Vigenere table as well, but some invitationals I've seen provide neither. What can I expect from regionals and states?


Ideally they should provide the Vigenere table, letters to numbers (A = 0, B = 1), Baconian table, modulo inverse (rarely), and texts for running key ciphers. They should also have frequency percentages for English and Spanish as well.

And unideally, you get nothing and have to do Vigenere the long way, write out the letters to numbers, manually calculate Baconian, and memorize the modulo inverse table as well as frequencies of English and Spanish letters. However this normally only comes up with student-made tests so I wouldn't worry about it at a higher level.


For frequencies, I meant the frequency of the letters in a particular ciphertext. Usually seen on tests below the question, where you can fill in the plaintext letters.

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Re: Codebusters C

Postby jimmy-bond » January 31st, 2019, 6:53 pm

mpnobivucyxtz wrote:For frequencies, I meant the frequency of the letters in a particular ciphertext. Usually seen on tests below the question, where you can fill in the plaintext letters.

Yeah, they'll usually have that. If they do not provide it, the test maker just hates children
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Re: Codebusters C

Postby TheChiScientist » January 31st, 2019, 6:54 pm

jimmy-bond wrote:
mpnobivucyxtz wrote:For frequencies, I meant the frequency of the letters in a particular ciphertext. Usually seen on tests below the question, where you can fill in the plaintext letters.

Yeah, they'll usually have that. If they do not provide it, the test maker just hates children

^Facts. :( Try to memorize them the best you can in this case.
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Re: Codebusters C

Postby Name » January 31st, 2019, 10:25 pm

TheChiScientist wrote:
jimmy-bond wrote:
mpnobivucyxtz wrote:For frequencies, I meant the frequency of the letters in a particular ciphertext. Usually seen on tests below the question, where you can fill in the plaintext letters.

Yeah, they'll usually have that. If they do not provide it, the test maker just hates children

^Facts. :( Try to memorize them the best you can in this case.

The average overall frequency table really isn't that useful, these are usually shorter quotes where frequencies can be skewed. Just know generally what is more common. The frequency of the particular cipher is more useful, but at least for aristocrats, I find word patterns are more useful, and not having the frequencies shouldn't be a huge problem. If they want to give a patristocrat with no frequencies though... Yeah have fun. I can't even do them with frequencies lol
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Re: Codebusters C

Postby Anonymous15 » February 4th, 2019, 1:49 pm

Hey guys!

Do you know what the difference between K1, K2, and random alphabets are? I can't find a good definition online.

Also, for patristocrats, do you know what method is best to use? I know there are five listed on the wiki for monoalphabetic ciphers, but sometimes they don't always work when the spacings are messed up. For example, as has been said on this thread before, letter frequencies don't always work because the text can be so short.

Thanks!

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Re: Codebusters C

Postby UTF-8 U+6211 U+662F » February 4th, 2019, 5:37 pm

Anonymous15 wrote:Hey guys!

Do you know what the difference between K1, K2, and random alphabets are? I can't find a good definition online.

Also, for patristocrats, do you know what method is best to use? I know there are five listed on the wiki for monoalphabetic ciphers, but sometimes they don't always work when the spacings are messed up. For example, as has been said on this thread before, letter frequencies don't always work because the text can be so short.

Thanks!

http://www.cryptogram.org/wp-content/th ... togram.pdf for your first question

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Re: Codebusters C

Postby pepperonipi » February 4th, 2019, 6:29 pm

Anonymous15 wrote:Hey guys!

Do you know what the difference between K1, K2, and random alphabets are? I can't find a good definition online.

Also, for patristocrats, do you know what method is best to use? I know there are five listed on the wiki for monoalphabetic ciphers, but sometimes they don't always work when the spacings are messed up. For example, as has been said on this thread before, letter frequencies don't always work because the text can be so short.

Thanks!


1. K1 is when there is a keyword in the plaintext and K2 is when there is a keyword in the ciphertext. I believe random alphabets are, well, random alphabets - no particular order. Definitely check out the link UTF posted before this.

2. I don't know of any "superb, easy, ultra quick" method for patristocrats because I don't think one exists. Just keep guessing and keep an open mind because some words may be way different than the words you are thinking they are. For example, you could think seeing "TH" must correspond to "THE" when it actually corresponded to the end of "FIFTH."

Good luck!
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