Codebusters C

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

Postby Name » September 9th, 2018, 10:07 pm

hippo9 wrote:
Answer
ALSOPLEASEGIVEYOURDECRYPTIONKEY


Decode this Baconian cipher. (Uses the 24 letter cipher alphabet)
ThinK todAy sIxty fROgS sToLe MaGIc


The answer also asked for the decryption key...

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

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Re: Codebusters C

Postby hippo9 » September 9th, 2018, 10:37 pm

Name wrote:
hippo9 wrote:
Answer
ALSOPLEASEGIVEYOURDECRYPTIONKEY


Decode this Baconian cipher. (Uses the 24 letter cipher alphabet)
ThinK todAy sIxty fROgS sToLe MaGIc


The answer also asked for the decryption key...

Also do you mean encode the text?

Oh sorry its
Answer
a=7 b=5


Also no, it's decoding from that ciphertext to plaintext if you need further explanation just ask.
"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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Re: Codebusters C

Postby Name » September 10th, 2018, 8:29 am

hippo9 wrote:
Name wrote:
hippo9 wrote:
Answer
ALSOPLEASEGIVEYOURDECRYPTIONKEY


Decode this Baconian cipher. (Uses the 24 letter cipher alphabet)
ThinK todAy sIxty fROgS sToLe MaGIc


The answer also asked for the decryption key...

Also do you mean encode the text?

Oh sorry its
Answer
a=7 b=5


Also no, it's decoding from that ciphertext to plaintext if you need further explanation just ask.


What? I thought encoded baconian cipher was like aaaaa is a aaaab is b aaaba is c etc
SW 16-17 Syosset 18-21. Previous main events: Microbe, Invasive, Herp, Matsci, Fermi
Hoping to do Astro, Code, and Ornith next year
2018-19 highlights
mit- 1st code, 3rd fermi
cornell- 1st fermi
states- 1st fermi, 3rd astro, 3rd code
18 medals

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Re: Codebusters C

Postby hippo9 » September 10th, 2018, 9:50 am

Name wrote:What? I thought encoded baconian cipher was like aaaaa is a aaaab is b aaaba is c etc

Explanation
It is, but you can convert that to a regular text with the two typefaces representing a/b or 0/1 depending on whether you're using binary or letters, which in the case above the lowercase was a and the uppercase was b

Carry on.
"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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Re: Codebusters C

Postby Name » September 10th, 2018, 12:32 pm

Oh.
hippo9 wrote:
Decode this Baconian cipher. (Uses the 24 letter cipher alphabet)
ThinK todAy sIxty fROgS sToLe MaGIc

answer
scioly

Invert the following encryption matrix
| 5 7|
| 2 1|
ESRKPWPDJZ was encoded using the previous matrix. Using the inverted matrix decode the cipher text
SW 16-17 Syosset 18-21. Previous main events: Microbe, Invasive, Herp, Matsci, Fermi
Hoping to do Astro, Code, and Ornith next year
2018-19 highlights
mit- 1st code, 3rd fermi
cornell- 1st fermi
states- 1st fermi, 3rd astro, 3rd code
18 medals

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Re: Codebusters C

Postby trdd » September 13th, 2018, 7:51 am

This one should be an easy one for anyone out there:
GUVF VF N FGNAQNEQ NAQ PBZZBA EBG GUVEGRRA PNRFNE PVCURE. UBJ DHVPXYL QVQ LBH FBYIR VG JVGUBHG HFVAT BAYVAR ERFBHEPRF?

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Re: Codebusters C

Postby trdd » September 13th, 2018, 8:01 am

Per (f.vi.) at least one of them has to be in Spanish for State and Nationals. So here's an easy standard one in Spanish. It is the first verse of a ridiculous hyperbolic poem: Try to solve it by hand without computers and post how fast you did.
FV QVBF HA QVN PRTNEN GBQN SHRAGR QR YHM, RY HAVIREFB FR NYHZOENEVN PBA RFBF BWBF DHR GVRARF GH.

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Re: Codebusters C

Postby Birdmusic » September 13th, 2018, 5:11 pm

trdd wrote:This one should be an easy one for anyone out there:
GUVF VF N FGNAQNEQ NAQ PBZZBA EBG GUVEGRRA PNRFNE PVCURE. UBJ DHVPXYL QVQ LBH FBYIR VG JVGUBHG HFVAT BAYVAR ERFBHEPRF?

Why did this take me so long? Probs cuz i tried counting letter frequency for like ten minutes before giving up
This is a standard and common rot thirteen shift cipher. How quickly did you solve it without using online resources?
I like birds.

2018 Results
R/S
Crime Busters: 1/2
Disease Detectives: 1/5
Hovercraft (both builds failed, rip): 11/9

2019 Results
GGSO/R/S
Disease Detectives: 6/3/10
Circuit lab:11/4/-
Sounds:3/2/1
Protein: -/-/6

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Re: Codebusters C

Postby Birdmusic » September 15th, 2018, 5:43 pm

Name wrote:Oh.
Invert the following encryption matrix
| 5 7|
| 2 1|
ESRKPWPDJZ was encoded using the previous matrix. Using the inverted matrix decode the cipher text


Answer?
Work:
Inverse is
|1 -7| *23 (the multiplicative inverse mod 26 of the determinant of the matrix, -9 or17)
|-2 5|

|23 21|
|6 11| (mod 26)


The code made into numbers is 4,18, 17, 10, 15, 22, 15, 3, 9, 25
After multiplying:
CODEBUSTERS
I like birds.

2018 Results
R/S
Crime Busters: 1/2
Disease Detectives: 1/5
Hovercraft (both builds failed, rip): 11/9

2019 Results
GGSO/R/S
Disease Detectives: 6/3/10
Circuit lab:11/4/-
Sounds:3/2/1
Protein: -/-/6

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Re: Codebusters C

Postby Name » September 15th, 2018, 5:46 pm

Birdmusic wrote:
Name wrote:Oh.
Invert the following encryption matrix
| 5 7|
| 2 1|
ESRKPWPDJZ was encoded using the previous matrix. Using the inverted matrix decode the cipher text


Answer?
Work:
Inverse is
|1 -7| *23 (the multiplicative inverse mod 26 of the determinant of the matrix, -9 or17)
|-2 5|

|23 21|
|6 11| (mod 26)


The code made into numbers is 4,18, 17, 10, 15, 22, 15, 3, 9, 25
After multiplying:
CODEBUSTERS


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

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Re: Codebusters C

Postby Birdmusic » September 16th, 2018, 2:31 pm

Encrypt the message “Affine cipher” with an affine cipher where a=7 and b=12.
I like birds.

2018 Results
R/S
Crime Busters: 1/2
Disease Detectives: 1/5
Hovercraft (both builds failed, rip): 11/9

2019 Results
GGSO/R/S
Disease Detectives: 6/3/10
Circuit lab:11/4/-
Sounds:3/2/1
Protein: -/-/6

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Re: Codebusters C

Postby Name » September 16th, 2018, 3:12 pm

Birdmusic wrote:Encrypt the message “Affine cipher” with an affine cipher where a=7 and b=12.


Answer
MVVQZO AQNJOB


(I think this is how RSA works)
The public key is c = m^5 mod 91
Find the private key
SW 16-17 Syosset 18-21. Previous main events: Microbe, Invasive, Herp, Matsci, Fermi
Hoping to do Astro, Code, and Ornith next year
2018-19 highlights
mit- 1st code, 3rd fermi
cornell- 1st fermi
states- 1st fermi, 3rd astro, 3rd code
18 medals

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

Postby UTF-8 U+6211 U+662F » September 16th, 2018, 4:51 pm

Name wrote:
Birdmusic wrote:Encrypt the message “Affine cipher” with an affine cipher where a=7 and b=12.


Answer
MVVQZO AQNJOB


(I think this is how RSA works)
The public key is c = m^5 mod 91
Find the private key

I don't do this event, but yay codes!
Answer




And the result which I'm pretty sure is right:

And that's why you should always choose large primes.


Decode LCHSYZOJHEAOJODYCNEWEHDIQBGD, which was encrypted using the Vigenère cipher with a key of TOWEL.

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Re: Codebusters C

Postby Name » September 16th, 2018, 5:05 pm

UTF-8 U+6211 U+662F wrote:
Name wrote:(I think this is how RSA works)
The public key is c = m^5 mod 91
Find the private key

I don't do this event, but yay codes!
Answer




And the result which I'm pretty sure is right:

And that's why you should always choose large primes.


Decode LCHSYZOJHEAOJODYCNEWEHDIQBGD, which was encrypted using the Vigenère cipher with a key of TOWEL.



Im pretty sure its
Answer
m^5 mod 91
Primes are 7 annd 13
Subtract one from each so 6 and 12
6*12=72
5X=1mod72
X=29
=c^29 mod 91

I might be wrong im not familiar with RSA
SW 16-17 Syosset 18-21. Previous main events: Microbe, Invasive, Herp, Matsci, Fermi
Hoping to do Astro, Code, and Ornith next year
2018-19 highlights
mit- 1st code, 3rd fermi
cornell- 1st fermi
states- 1st fermi, 3rd astro, 3rd code
18 medals

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

Postby UTF-8 U+6211 U+662F » September 16th, 2018, 5:58 pm

Name wrote:
UTF-8 U+6211 U+662F wrote:
Name wrote:(I think this is how RSA works)
The public key is c = m^5 mod 91
Find the private key

I don't do this event, but yay codes!
Answer




And the result which I'm pretty sure is right:

And that's why you should always choose large primes.


Decode LCHSYZOJHEAOJODYCNEWEHDIQBGD, which was encrypted using the Vigenère cipher with a key of TOWEL.



Im pretty sure its
Answer
m^5 mod 91
Primes are 7 annd 13
Subtract one from each so 6 and 12
6*12=72
5X=1mod72
X=29
=c^29 mod 91

I might be wrong im not familiar with RSA

The expressions are equivalent (to the best of my mathematical knowledge)

Edit: No they're not, sorry.
I believe what you calculated is the expression for the public key. For the values I tested, , which means you're effectively multiplying the expression for the public key by 1. Why , I have no idea.


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