Codebusters C

Umaroth
Member
Member
Posts: 111
Joined: February 10th, 2018, 8:51 pm
Division: C
State: CA
Location: Kraemer Room 504, Troy Room 901, or studying at my dining table

Re: Codebusters C

Postby Umaroth » 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.
Proud Padre of Kraemer SciOly
Kraemer SciOly Co-Captain 2018-2019
Dank Memes Area Homeschool Juggernaut 2018-2019
Kraemer SciOly Semi-Official Head Coach 2019-2020
2020 Tryouts: Circuit, Code, Detector, DP, GeoMaps, Machines

Umaroth's Userpage

User avatar
Name
Member
Member
Posts: 304
Joined: January 21st, 2018, 4:41 pm
Division: C
State: NY
Location: Syosset

Re: Codebusters C

Postby Name » 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?
South Woods MS/Syosset HS
Favorite Past Events: Microbe, Invasive, Matsci, Fermi
Events!: Astro, Code, Fossils

"The more cheese, the more holes. The more holes the less cheese. Therefore the more cheese, the less cheese."

Jacobi
Exalted Member
Exalted Member
Posts: 137
Joined: September 4th, 2018, 7:47 am

Re: Codebusters C

Postby Jacobi » 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.

User avatar
jlordhe
Member
Member
Posts: 30
Joined: September 16th, 2018, 10:14 pm
Division: C
State: CA
Contact:

Re: Codebusters C

Postby jlordhe » October 4th, 2018, 4:58 pm

Do you have to be extremely good at math for this event?
Events I Might Do and Want to Do: Fossils, Wright Stuff, Herpetology, Water Quality, Boomilever

User avatar
Unome
Moderator
Moderator
Posts: 4120
Joined: January 26th, 2014, 12:48 pm
Division: Grad
State: GA
Location: somewhere in the sciolyverse

Re: Codebusters C

Postby Unome » 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).
Userpage
Chattahoochee High School Class of 2018
Georgia Tech Class of 2022

Opinions expressed on this site are not official; the only place for official rules changes and FAQs is soinc.org.

User avatar
TheChiScientist
Member
Member
Posts: 676
Joined: March 11th, 2018, 11:25 am
Division: Grad
State: IL
Location: Suffering in a college class

Re: Codebusters C

Postby TheChiScientist » October 4th, 2018, 6:47 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).
Most ciphers just require studying and memorization. Make sure you know your alphabet very well. ;) As Unome said only a few require actual number crunching.
A Science Olympian from 2015 - 2019
Medal Count:30 8-)
School:Crystal Lake Central High School Wiki
Assassinator #119 and Co-Conspirator in #120
President of The Builder Cult. Builders rise up!

cryptoderes
Member
Member
Posts: 3
Joined: October 5th, 2018, 8:51 am

Re: Codebusters C

Postby cryptoderes » October 5th, 2018, 4:00 pm

Can someone do a quick walkthrough on how to solve an RSA cipher?

UTF-8 U+6211 U+662F
Exalted Member
Exalted Member
Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

Re: Codebusters C

Postby UTF-8 U+6211 U+662F » October 5th, 2018, 4:31 pm

Can someone do a quick walkthrough on how to solve an RSA cipher?
Does this help?

cryptoderes
Member
Member
Posts: 3
Joined: October 5th, 2018, 8:51 am

Re: Codebusters C

Postby cryptoderes » October 6th, 2018, 12:24 pm

Can someone do a quick walkthrough on how to solve an RSA cipher?
Does this help?
Ah yes, thank you so much!

UTF-8 U+6211 U+662F
Exalted Member
Exalted Member
Posts: 1518
Joined: January 18th, 2015, 7:42 am
Division: C
State: PA

Re: Codebusters C

Postby UTF-8 U+6211 U+662F » October 6th, 2018, 1:53 pm

Can someone do a quick walkthrough on how to solve an RSA cipher?
Does this help?
Ah yes, thank you so much!
Just make sure you know encryption and decryption :)


Return to “2019 Lab Events”

Who is online

Users browsing this forum: No registered users and 1 guest