Codebusters C

TheWood
Member
Member
Posts: 14
Joined: Wed Feb 20, 2019 2:30 pm
Division: C
State: GA
Has thanked: 0
Been thanked: 0

Re: Codebusters C

Post by TheWood »

Sorry mb for not posting earlier.

Find the inverse of the following hill encryption key:
BRA
CEL
ETS
Brookwood High School (Head Officer)
Top
KITN1931
Member
Member
Posts: 1
Joined: Wed Feb 27, 2019 10:19 pm
Has thanked: 0
Been thanked: 0

Re: Codebusters C

Post by KITN1931 »

Can someone give me tips on solving patristocrats????
Top
CongminhTran
Member
Member
Posts: 2
Joined: Thu Oct 12, 2017 4:17 pm
Has thanked: 0
Been thanked: 0

Re: Codebusters C

Post by CongminhTran »

Hey guys,

I was just wondering if any of you guys could help me with the Hill Cipher, both decryption and encryption?

For encryption, how do you make an encryption matrix given plaintext- ciphertext letter pairs?

For decryption, how do you make a decryption matrix given plaintext-ciphertext letter pairs? Also, how do you decrypt when given a key and some ciphertext? Lastly, what if they ask you to produce a decryption matrix given only some plaintext (with number values all arranged in a matrix)? I was asking because at the Regionals test for my school, a couple of Hill Cipher questions where you had to produce A (the other one was THE) decryption matrix showed up, and we had no idea on how to do them.

If you guys could try to help, I would very much appreciate that!
Top
User avatar
jimmy-bond
Member
Member
Posts: 417
Joined: Mon Jan 08, 2018 11:25 pm
Division: Grad
State: OH
Pronouns: He/Him/His
Has thanked: 11 times
Been thanked: 10 times

Re: Codebusters C

Post by jimmy-bond »

CongminhTran wrote:Hey guys,

I was just wondering if any of you guys could help me with the Hill Cipher, both decryption and encryption?

For encryption, how do you make an encryption matrix given plaintext- ciphertext letter pairs?

For decryption, how do you make a decryption matrix given plaintext-ciphertext letter pairs? Also, how do you decrypt when given a key and some ciphertext? Lastly, what if they ask you to produce a decryption matrix given only some plaintext (with number values all arranged in a matrix)? I was asking because at the Regionals test for my school, a couple of Hill Cipher questions where you had to produce A (the other one was THE) decryption matrix showed up, and we had no idea on how to do them.

If you guys could try to help, I would very much appreciate that!
KITN1931 wrote:Can someone give me tips on solving patristocrats????
These should go under the Code Busters thread under "Lab Events".
PCHS, HI '21 | CWRU, OH '25
Code(16), DD(40), FQ(39),4&6(36), WQ(27)
CriB(26), DP (11), FF(1), MM(14), P&P(6)
CriB(36), DD(35), FF(2), MM(20)
Top
User avatar
Name
Member
Member
Posts: 434
Joined: Sun Jan 21, 2018 4:41 pm
Division: C
State: NY
Pronouns: He/Him/His
Has thanked: 49 times
Been thanked: 46 times

Re: Codebusters C

Post by Name »

TheWood wrote:Sorry mb for not posting earlier.

Find the inverse of the following hill encryption key:
BRA
CEL
ETS
This year's rules doesn't cover inverting 3x3 hill keys.
However it should be 
HUV
SIL
EDE
(I kinda stole this question, but I really liked the way they presented the Bacon cipher)
ADELE DEALT DEREK LAMPS DATED AS THE BLUNT CELLO DEALT FREED ACTORS GETS A DEATH FLYER EAGLE A YEAR YELLS OFTEN A ROAD
The first 4 letters in the ciphertext is "real"
South Woods MS, Syosset HS '21
BirdSO TD/ES
Past Events: Microbe, Invasive, Matsci, Fermi, Astro, Code, Fossils 
1st place MIT Codebusters 2019-2020
1st place NYS Fermi Questions (2019), Astronomy and Codebusters (2021)
Science Olympiad Founder's Scholarship winner
Top
User avatar
dragonfruit35
Exalted Member
Exalted Member
Posts: 296
Joined: Sat Feb 28, 2015 7:49 am
Division: Grad
State: VA
Pronouns: She/Her/Hers
Has thanked: 7 times
Been thanked: 1 time

Re: Codebusters C

Post by dragonfruit35 »

Name wrote: (I kinda stole this question, but I really liked the way they presented the Bacon cipher)
ADELE DEALT DEREK LAMPS DATED AS THE BLUNT CELLO DEALT FREED ACTORS GETS A DEATH FLYER EAGLE A YEAR YELLS OFTEN A ROAD
The first 4 letters in the ciphertext is "real"

Hmmm... KINDA... :lol:
REALITY BEATS FANTASY
PS: I think you added an extra "S" at the end of ACTORS, because that makes six letters in the group.
tjhsst '20
virginia tech '24
2x codebusters national medalist

"it's not a pen, it's a principle!" - annie edison
Top
User avatar
Name
Member
Member
Posts: 434
Joined: Sun Jan 21, 2018 4:41 pm
Division: C
State: NY
Pronouns: He/Him/His
Has thanked: 49 times
Been thanked: 46 times

Re: Codebusters C

Post by Name »

dragonfruit35 wrote:
Name wrote: (I kinda stole this question, but I really liked the way they presented the Bacon cipher)
ADELE DEALT DEREK LAMPS DATED AS THE BLUNT CELLO DEALT FREED ACTORS GETS A DEATH FLYER EAGLE A YEAR YELLS OFTEN A ROAD
The first 4 letters in the ciphertext is "real"

Hmmm... KINDA... :lol:
REALITY BEATS FANTASY
PS: I think you added an extra "S" at the end of ACTORS, because that makes six letters in the group.
Yup and oops yeah I did.
South Woods MS, Syosset HS '21
BirdSO TD/ES
Past Events: Microbe, Invasive, Matsci, Fermi, Astro, Code, Fossils 
1st place MIT Codebusters 2019-2020
1st place NYS Fermi Questions (2019), Astronomy and Codebusters (2021)
Science Olympiad Founder's Scholarship winner
Top
User avatar
dragonfruit35
Exalted Member
Exalted Member
Posts: 296
Joined: Sat Feb 28, 2015 7:49 am
Division: Grad
State: VA
Pronouns: She/Her/Hers
Has thanked: 7 times
Been thanked: 1 time

Re: Codebusters C

Post by dragonfruit35 »

Decode this Vigenere-encrypted text where the five-letter key saved physicists from using Coulomb’s law infinitely for the rest of their lives.

zhy w-xoefv wwuudk felg atscvw g cifvacngj zhul ay ih klgtcu wwucdahrcme
The word “e-field” is part of the plaintext.
The key is GAUSS.
tjhsst '20
virginia tech '24
2x codebusters national medalist

"it's not a pen, it's a principle!" - annie edison
Top
starfruit
Member
Member
Posts: 29
Joined: Sat Feb 24, 2018 3:51 am
Division: C
State: VA
Pronouns: She/Her/Hers
Has thanked: 0
Been thanked: 0

Re: Codebusters C

Post by starfruit »

the e-field equals zero inside a conductor that is in static equilibrium
code/forensics/it's about time
:!: :!: :!:
Top
User avatar
dragonfruit35
Exalted Member
Exalted Member
Posts: 296
Joined: Sat Feb 28, 2015 7:49 am
Division: Grad
State: VA
Pronouns: She/Her/Hers
Has thanked: 7 times
Been thanked: 1 time

Re: Codebusters C

Post by dragonfruit35 »

starfruit wrote:the e-field equals zero inside a conductor that is in static equilibrium
Correct! Your turn.
tjhsst '20
virginia tech '24
2x codebusters national medalist

"it's not a pen, it's a principle!" - annie edison
Top

Return to “2019 Question Marathons”