Codebusters C

User avatar
OrigamiPlanet
Member
Member
Posts: 146
Joined: August 6th, 2017, 12:15 pm
Division: C
State: PA
Contact:

Re: Codebusters C

Postby OrigamiPlanet » April 16th, 2019, 1:25 pm

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?
Div. C - Cumberland Valley High School

Events: Battle at Valley Forge/MC Barons
Codebusters (3/3); Dynamic Planet (3/1); Astronomy (-/2)

Substitute in Event
Geologic Mapping (-/2)

Email me for anything!

User avatar
pepperonipi
Member
Member
Posts: 36
Joined: January 21st, 2019, 11:38 am
Division: C
State: FL
Location: ヽ(͡◕ ͜ʖ ͡◕)ノ

Re: Codebusters C

Postby pepperonipi » April 16th, 2019, 4:36 pm

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.
Boca Raton Community High School
My Wiki | School Wiki
My Events

2019
Season Events:
Image
Image
Image
National Trial Event:
Image

will0416
Member
Member
Posts: 12
Joined: February 18th, 2019, 7:43 am
Division: C
State: OH

Re: Codebusters C

Postby will0416 » May 5th, 2019, 6:31 pm

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)?
Mason ‘22
2019 Nats:
Code - 4
Mission - 4

Anomaly
Exalted Member
Exalted Member
Posts: 570
Joined: February 17th, 2017, 10:46 am
Division: C
State: PA
Location: Somewhere in the known or unknown universe

Re: Codebusters C

Postby Anomaly » May 6th, 2019, 2:00 pm

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
Orefield MS SO 2015-2018, Parkland HS SO 2019
Medal/Ribbon Count
Invitational: 25
Regional: 16
State: 5
Events:
Anatomy and Physiology, Codebusters, Disease Detectives, Write It Do It

will0416
Member
Member
Posts: 12
Joined: February 18th, 2019, 7:43 am
Division: C
State: OH

Re: Codebusters C

Postby will0416 » May 6th, 2019, 3:02 pm

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
Member
Member
Posts: 2
Joined: September 13th, 2016, 7:04 pm
Division: C
State: MI

Re: Codebusters C

Postby AZ_120 » May 9th, 2019, 2:04 pm

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
Coach
Coach
Posts: 197
Joined: May 2nd, 2009, 5:02 pm
Division: Grad
State: PA

Re: Codebusters C

Postby GoldenKnight1 » May 10th, 2019, 3:04 am

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
Member
Member
Posts: 4
Joined: November 19th, 2018, 6:28 am
Division: C
State: DC

Re: Codebusters C

Postby eab2114 » May 17th, 2019, 5:41 am

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.

User avatar
dragonfruit35
Exalted Member
Exalted Member
Posts: 277
Joined: February 28th, 2015, 7:49 am
Division: C
State: VA
Location: TJHSST

Re: Codebusters C

Postby dragonfruit35 » May 19th, 2019, 7:17 am

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.

2018
(VT/FFX/Reg/States/Nats)
MV 1/1/5/-/- Mission 3/4/4/-/- Herp 7/2/4/-/-
WiFi -/-/-/4/13 Indoor Bottle Rocket -/-/-/1/- Code -/-/-/-/1

2019
(Duke/Reg/Cornell/States/Nats)
MV 2/3/7/3/10 Mission 3/7/- Sounds 4/2/- Code 3/1/1/1/5 Herp -/-/11/1/26


Goooooooo Colonials!!!


Return to “Lab Events”

Who is online

Users browsing this forum: No registered users and 2 guests