Codebusters C

[trdd]

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?

[trdd]

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.

[Birdmusic]

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 (Click to Show Hidden Text)

This is a standard and common rot thirteen shift cipher. How quickly did you solve it without using online resources?

[Birdmusic]

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? (Click to Show Hidden Text)

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

[b]|23 21|
|6 11| (mod 26)[/b]

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

[Name]

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? (Click to Show Hidden Text)

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

[b]|23 21|
|6 11| (mod 26)[/b]

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

yup. your turn

[Birdmusic]

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

[Name]

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

Answer (Click to Show Hidden Text)

MVVQZO AQNJOB

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

[UTF-8 U+6211 U+662F]

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

Answer (Click to Show Hidden Text)

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!

Click to Show 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.

[Name]

(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!

Click to Show 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 (Click to Show Hidden Text)

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

[UTF-8 U+6211 U+662F]

(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!

Click to Show 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 (Click to Show Hidden Text)

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.