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### Re: Codebusters C

Posted: September 16th, 2018, 3:11 pm
How are you guys studying for this as a team? I want to know so I can get cracking with my teammates.

### Re: Codebusters C

Posted: September 16th, 2018, 3:16 pm
How are you guys studying for this as a team? I want to know so I can get cracking with my teammates.

first just learn how to encode and decode all the different type of ciphers
once you got that down, start practcing by writing ciphers for each other to solve

### Re: Codebusters C

Posted: September 19th, 2018, 1:03 pm
How are you guys studying for this as a team? I want to know so I can get cracking with my teammates.

first just learn how to encode and decode all the different type of ciphers
once you got that down, start practcing by writing ciphers for each other to solve
Furthering that point, once you guys all have a general idea of each code it's probably best that only two of the three people specialize on a specific cipher, as you want to be specialized to work best at any code. Having two people will definitely work better than one person, since at least one other person can quickly look for errors should they be present while the third one focuses on a different code. You don't all want to focus as a group though, since you still want to keep efficiency. This also means the xenocrypt in Spanish, at least two people should know or try and learn some Spanish grammar/vocabulary.

### Re: Codebusters C

Posted: September 20th, 2018, 7:08 am
Any good advice on solving patristocrats?

### Re: Codebusters C

Posted: September 20th, 2018, 7:24 am
Any good advice on solving patristocrats?
Finding repeating chunks in the problem can allow you to see patterns and guess what word it is (probably "the", or another another commonly used word). Letter frequency also helps a lot if you know the order (ETAOIN)

### Re: Codebusters C

Posted: September 23rd, 2018, 9:51 pm
Since it isn't specified in the rules, does anyone know how test writers unwittingly giving us non invertible Hill cipher matrices will be prevented? This would probably cause a lot of frustration among teams.

### Re: Codebusters C

Posted: September 23rd, 2018, 10:07 pm
Since it isn't specified in the rules, does anyone know how test writers unwittingly giving us non invertible Hill cipher matrices will be prevented? This would probably cause a lot of frustration among teams.
For a 2x2 cipher in order to be invertable ad-bc mod 26 has to be coprime to 26
Under the current rules I don't think we have to invert 3x3s?

### Re: Codebusters C

Posted: September 26th, 2018, 2:55 pm
Since it isn't specified in the rules, does anyone know how test writers unwittingly giving us non invertible Hill cipher matrices will be prevented? This would probably cause a lot of frustration among teams.
For a 2x2 cipher in order to be invertable ad-bc mod 26 has to be coprime to 26
Under the current rules I don't think we have to invert 3x3s?

Eh... I would say yes.

As someone said, "Prepare for everything so you're ready for everything."
If no one said that, someone should have.

### Re: Codebusters C

Posted: October 4th, 2018, 4:58 pm
Do you have to be extremely good at math for this event?

### Re: Codebusters C

Posted: October 4th, 2018, 6:04 pm
Do you have to be extremely good at math for this event?
Not for most ciphers. There are a few that require significant math background (e.g. Hill cipher).