question:

HITSS{5X65Z1ZXZ10F_E1LI3J}

files: [script.py](script(4).py)
- based on the name we can assume it's a substitution cipher

looking at the script we get:

alpha = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ{}_1234567890'
key   = 'QWERTPOIUYASDFGLKJHZXCVMNB{}_1234567890'


text = <flag>

def encrypter(text,key):
    encrypted_msg = ''
    for i in text:
        index = alpha.index(i)
        encrypted_msg += key[index]
    # print(encrypted_msg)
    return encrypted_msg

- looks like a 1 for 1 substitution using the included key.

1) copy paste the flag into a txt called flag
2) translate from key to alpha `cat flag | tr 'QWERTPOIUYASDFGLKJHZXCVMNB{}_1234567890' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ{}_1234567890'
`
- output:

SHELL{5U65T1TUT10N_C1PH3R} 

**flag: SHELL{5U65T1TUT10N_C1PH3R}**

Original writeup (https://github.com/ivanchubb/CTF-Writeups/tree/main/2021/S.H.E.L.L.%20CTF/Subsi).