Metadata-Version: 2.1
Name: etao
Version: 1.0.1
Summary: Simple cryptanalysis library
Home-page: https://github.com/jamchamb/etao
Author: James Chambers
Author-email: jameschambers2@gmail.com
License: GPLv3
Keywords: cryptography,cryptanalysis,ciphers
Platform: UNKNOWN

etao
====
.. image:: https://badge.fury.io/py/etao.svg
    :target: https://badge.fury.io/py/etao
.. image:: https://travis-ci.org/jamchamb/etao.svg?branch=master
    :target: https://travis-ci.org/jamchamb/etao
.. image:: https://img.shields.io/codecov/c/github/jamchamb/etao.svg?maxAge=2592000
   :target: https://codecov.io/github/jamchamb/etao

etao is a simple Python library that assists in the creation
of cryptanalysis tools. It takes care of common low-level tasks
such as converting letters to numeric values or splitting a buffer
into a bit stream or series of fixed-size blocks, as well as higher-level
things like frequency analysis.

Installation
------------
Install with pip::

    pip install etao

As of version 1.0.0 this library switched from Python 2 to Python 3; for
Python 2 use version 0.6.0.

Example Application
-------------------
The following is a Caesar cipher solving tool that uses etao's frequency
analysis functions and built-in ciphers.

.. code:: python

 #!/usr/bin/env python
 # Caesar cipher solver
 import argparse
 from etao import CaesarCipher, NgramFrequencyScorer
 from etao.freq import ENGLISH_DIGRAMS


 def main():
     parser = argparse.ArgumentParser(description="Caesar cipher solver")
     parser.add_argument('ciphertext', type=str, help='text to decipher')
     args = parser.parse_args()

     scorer = NgramFrequencyScorer(freq=ENGLISH_DIGRAMS)

     # Get every Caesar shift of the ciphertext
     shifts = [CaesarCipher(n).decrypt(args.ciphertext) for n in range(26)]

     # Score each shift according to English character frequency.
     # Get tuples that pair the score with the text.
     scored_shifts = [(scorer.score(shift), shift) for shift in shifts]

     # Sort by score, descending order
     scored_shifts.sort(reverse=True)

     # Print the top 3 results
     for result in scored_shifts[0:3]:
         print('"%s" (%02d%%)' % (result[1], int(result[0] * 100)))


 if __name__ == "__main__":
     main()

Here's what it looks like in action:

.. code-block:: console

    $ ./caesar_solver.py "O GQFSOAWBU QCASG OQFCGG HVS GYM. WH VOG VODDSBSR PSTCFS, PIH HVSFS WG BCHVWBU HC QCADOFS WH HC BCK."
    "A SCREAMING COMES ACROSS THE SKY. IT HAS HAPPENED BEFORE, BUT THERE IS NOTHING TO COMPARE IT TO NOW." (75%)
    "U MWLYUGCHA WIGYM UWLIMM NBY MES. CN BUM BUJJYHYX VYZILY, VON NBYLY CM HINBCHA NI WIGJULY CN NI HIQ." (36%)
    "P HRGTPBXCV RDBTH PRGDHH IWT HZN. XI WPH WPEETCTS QTUDGT, QJI IWTGT XH CDIWXCV ID RDBEPGT XI ID CDL." (35%)


