# A Fine Cipher
## Overview
- 137 Points / 280 Solves
## Background
We have intercepted a message from a suspicious group. Can you help use break the code and reveal the hidden message?
Encryped Message: `JSNRZHIVJUCVIVFCVYBMVBDRZCXRIVBINCORBCSFHCBINOCRMHBD`
NOTE: Make sure you wrap the flag
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401222057.png)
## Find the flag
Hmm... That message looks like encoded in base32... However, it said "Encryped"...
After fumbling around, I found that the answer is in the challenge's title: "***Afine Cipher***"
> The affine cipher is a type of monoalphabetic substitution cipher, where each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter.
**Then, find a online tool that brute force the encrypted message. I'll use [dcore.fr](https://www.dcode.fr/affine-cipher):**
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401222245.png)
Found it!
- Flag: `RS{IFYOUAREINTERESTEDCHECKOUTMORECRYTPOCTFSATCRYPTOHACK}`
## Conclusion
What we've learned:
1. Deciphering Affine Cipher