dy-Dx

200 points

files included:

1MB

dY-Dx

Open

opening the file we see a very long ciphertext, however it is 18k lines long so it would be unwise of me to copy and paste it here

my pc after i attempt to paste 18k lines of text into gitbook

The ciphertext appears to be in base64 when reversed

Cyberchef

lets put the ciphertext into cyberchef, reverse it and decode from base64

Interesting, it seems to be the raw data of a png file

rendering it into an image:

we get the flag

flag: HNF23{(8x+2x)(3x+1)^1/2}