Our spies might have stolen crucial secret files from our enemies.
- secret.zip (a PASSWORD PROTECTED zip file)
Our data analyst team came to the conclusion that the essential secret information can be found within the secret.zip
But the file is protected by a password, and we don't know much about it:
- is it a password, a passphrase ?
- what characters compose the pass ? alpha, num, symbols ?
- what's the pass length ?
Also, our spies have found and stolen 3 pass files:
- pass-1.zip (a zip file containing a
.txtfile) - pass-2.zip (a zip file containing a
.txtfile) - pass-3.zip (a CORRUPTED zip file)
They led our analysts to the conclusion
that each pass-{N}.txt file's content,
are the 1st, 2nd and 3rd part of the password protecting the secret.zip
Unfortunately the pass-3.zip looks corrupted,
impossible to extract the pass-3.txt file from it.
Our security experts have a few theories about this corruption, they think this was corrupted on purpose.
A few techniques might have been used to cipher it, but the experts tend to think that a single-byte xor cipher might have been used here.
If only there was a way to check the integrity of a zip file... Some data in it that never changes, and that can be brute-forced ?
Decipher the pass-3.zip, and extract the data from secret.zip
To help you on your task here are some crucial resources:
- Official ZIP documentation
- About the XOR cipher
- Some useful Unix commands:
zip,unzip,zipdetails,xxd
Use your Gleam knowledge to:
- read data from file
- update it
- rewrite the file (or write to another file, if you prefer)
gleam run # Run the project
gleam test # Run the tests