Codebusters C

Test your knowledge of various Science Olympiad events.
TheWood
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Re: Codebusters C

Postby TheWood » February 28th, 2019, 4:42 pm

Sorry mb for not posting earlier.

Find the inverse of the following hill encryption key:
BRA
CEL
ETS
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KITN1931
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Re: Codebusters C

Postby KITN1931 » March 1st, 2019, 3:54 pm

Can someone give me tips on solving patristocrats????

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Re: Codebusters C

Postby CongminhTran » March 1st, 2019, 7:08 pm

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!

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jimmy-bond
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Re: Codebusters C

Postby jimmy-bond » March 1st, 2019, 7:20 pm

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".
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Season's over, I can sleep now.

2019 States
Code Busters(1), DD(1), FQ(2), Forensics(1), WQ(5)

2018 Nats
CriB(26), DP (11), FF(1), MM(14), P&P(6)

2017 Nats
CriB(36), DD(35), FF(2), MM(20)

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Re: Codebusters C

Postby Name » March 12th, 2019, 10:26 pm

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
answer
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"
SW 16-17 Syosset 18-21. Previous main events: Microbe, Invasive, Herp, Matsci, Fermi
Hoping to do Astro, Code, Ornith, and maybe Compound next year
2018-19 highlights
mit- 1st code, 3rd fermi
cornell- 1st fermi
states- 1st fermi, 3rd astro, 3rd code
19 medals

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dragonfruit35
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Re: Codebusters C

Postby dragonfruit35 » March 14th, 2019, 8:07 pm

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:

Answer
REALITY BEATS FANTASY


PS: I think you added an extra "S" at the end of ACTORS, because that makes six letters in the group.

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!!!

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Re: Codebusters C

Postby Name » March 14th, 2019, 8:37 pm

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:

Answer
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.
SW 16-17 Syosset 18-21. Previous main events: Microbe, Invasive, Herp, Matsci, Fermi
Hoping to do Astro, Code, Ornith, and maybe Compound next year
2018-19 highlights
mit- 1st code, 3rd fermi
cornell- 1st fermi
states- 1st fermi, 3rd astro, 3rd code
19 medals

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dragonfruit35
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Re: Codebusters C

Postby dragonfruit35 » March 15th, 2019, 11:28 am

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

hint:
The word “e-field” is part of the plaintext.


big hint:
The key is GAUSS.

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!!!

starfruit
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Re: Codebusters C

Postby starfruit » March 16th, 2019, 7:02 pm

the e-field equals zero inside a conductor that is in static equilibrium
2019 events-
potions&poisons/heredity/crimebusters/codebusters

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dragonfruit35
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Re: Codebusters C

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

starfruit wrote:the e-field equals zero inside a conductor that is in static equilibrium


Correct! Your turn.

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!!!

starfruit
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Re: Codebusters C

Postby starfruit » March 20th, 2019, 1:26 pm

Translate the following message into Affine when x=12 and y=3

skittles-taste the rainbow
2019 events-
potions&poisons/heredity/crimebusters/codebusters

UTF-8 U+6211 U+662F
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Re: Codebusters C

Postby UTF-8 U+6211 U+662F » March 20th, 2019, 1:49 pm

starfruit wrote:Translate the following message into Affine when x=12 and y=3

skittles-taste the rainbow

Answer
HSVXXFZH-XDHXZ XJZ ZDVDNPH?

Anomaly
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Re: Codebusters C

Postby Anomaly » March 20th, 2019, 3:15 pm

UTF-8 U+6211 U+662F wrote:
starfruit wrote:Translate the following message into Affine when x=12 and y=3

skittles-taste the rainbow

Answer
HSVXXFZH-XDHXZ XJZ ZDVDNPH?

wait, is it me or is that not a valid key? i thought that x can't be coprime with 26 or else it leads to letters being repeated...
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

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Riptide
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Re: Codebusters C

Postby Riptide » March 20th, 2019, 3:58 pm

Anomaly wrote:
UTF-8 U+6211 U+662F wrote:
starfruit wrote:Translate the following message into Affine when x=12 and y=3

skittles-taste the rainbow

Answer
HSVXXFZH-XDHXZ XJZ ZDVDNPH?

wait, is it me or is that not a valid key? i thought that x can't be coprime with 26 or else it leads to letters being repeated...

yeah I believe the letters would start repeating after half of the alphabet?
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Seven Lakes High School '19
Seven Lakes Junior High '15

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Re: Codebusters C

Postby hippo9 » March 20th, 2019, 4:05 pm

Riptide wrote:
Anomaly wrote:
UTF-8 U+6211 U+662F wrote:
Answer
HSVXXFZH-XDHXZ XJZ ZDVDNPH?

wait, is it me or is that not a valid key? i thought that x can't be coprime with 26 or else it leads to letters being repeated...

yeah I believe the letters would start repeating after half of the alphabet?

As evidenced by e and r both encoding to Z. (There's probably more, I just saw these)
"If we knew what we were doing, it wouldn’t be called research." - Albert Einstein

2018: Battery Buggy, Road Scholar, Roller Coaster
2019: Chemistry Lab, Codebusters, Disease Detectives, Fossils, Geologic Mapping, Sounds of Music


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