Lets download the file and check the content
That looks like binary but then that's a lot of space, well from experience I can tell that I'm meant to use stegsnow to solve this hehe
To install this tool you can use the command sudo apt install stegsnow
To use the tool
command:stegsnow -C simple.txt
┌──(bl4ck4non👽bl4ck4non-sec)-[~/Downloads/CTF/africa_cyberfest/cryptography]
└─$ stegsnow -C simple.txt
ÀCÒÔ{1òñ_jó57_à5_5èìïë3_4ñ_1ò_100ê5!!!}
Now, that's some weird cipher, that's what I thought at first😂.
But then, this is actually not a cipher hehe, it is an encoding, it's called a cyrillic encoding
We can decode this using this webpage
You can see we have some weird output, now lets select the "source encoding" and also the "displayed as" option
Now, we have a more resonable output
I was actually stuck here for a while because I thought this guy АCТФ{1тс_jу57_а5_5импл3_4с_1т_100к5!!!} was an encoding but then I thought wrong, it's actually a language lool.
We can translate this using google translator
Yup, that's our flag hehe
FLAG:-ACTF {1ts_ju57_a5_5impl3_4s_1t_100k5!!!}