Tags: hill-cipher invaders mj0ln1r crypto 

Rating:

# jack-and-jill

Ciphertext is given : `pgQVJFCohpccuyBSbwxcxpVZCAATRT`. A 2x2 matrix is given [[3,9],[4,7]].

By observing the description i found that this is a `hill cipher`. I quickly searched for the hill cipher decoder online. I used this site to decipher the text.

The deciphered text is **`hiTHEREwelcomeTOlinearALGEBRAZ`**

> `Flag : jctf{hiTHEREwelcomeTOlinearALGEBRAZ}`

## [Original Writeup](https://themj0ln1r.github.io/posts/jerseyctf23)

Original writeup (https://themj0ln1r.github.io/posts/jerseyctf23).