About

pystrfry a tool and Python 3 library for Linux for assisting in solving those annoying strfry CTF challenges that seem to be common in CTFs like ångstromCTF 2020 and DawgCTF 2020.

No additional requirements other than Linux and Python 3.

Installation

PyPi

# pip3 install pystrfry

Manual

$ git clone https://github.com/arinerron/pystrfry.git
$ cd pystrfry
# python3 setup.py install

Usage

Command Line Interface

Help Menu

$ strfry --help

usage: strfry [-h] [--processid PROCESSID] [--timestamp TIMESTAMP] [--decode] string

a tool for solving those annoying strfry CTF challenges

positional arguments:
  string                the string to manipulate

optional arguments:
  -h, --help            show this help message and exit
  --processid PROCESSID, --pid PROCESSID, -p PROCESSID
                        process id which called strfry
  --timestamp TIMESTAMP, --ts TIMESTAMP, -t TIMESTAMP
                        unix timestamp when strfry happened
  --decode, -d          switch to decode mode$

Example

$ strfry --pid=1337 --ts=1234 "i use arch btw"
ubs twir ec ha

$ strfry --pid=1337 --ts=1234 "ubs twir ec ha" --decode
i use arch btw

Python Library

>>> from strfry import *

>>> strfry('i use arch btw', pid=1337, ts=1234)
'ubs twir ec ha'

>>> unstrfry('ubs twir ec ha', pid=1337, ts=1234)
'i use arch btw'

>>> strfry('this will pull the current ts / pid if you dont specify')
'iutihtfwel usnsd  f oyroyi    t p/rphpctlcsle n dleiitu'

>>> strfry('this will pull the current ts / pid if you dont specify')
'ols tupeprn ftod ceit l sehic  rys i tn pwl/uyflhdiiu t'

>>> strfry('this will pull the current ts / pid if you dont specify')
'ft sult f ynn srhp top /eihlew ipi ecdl l itutc rudyois'