Stream Cipher

Implementation of stream cipher using block cipher i.e. AES ECB mode

Instructions

• Install and initilize virtualenv:

    pip install virtualenv
    virtualenv --python=python2.7 my-venv
  

• Activate/Deactivate virtualenv:

    source my-venv/bin/activate
    
    deactivate
  

• Install Python dependencies:

    pip install cryptography pytest
  

• Run test_AESCtr and excluding the my-venv folder:

    py.test --ignore=my-venv
  

• Run standard debugger pdb

    py.test -x --pdb --ignore=my-venv
  

• RUN GUI debugger pudb and pytest-pudb:

    pip install pudb pytest-pudb
    py.test -x --pudb --ignore=my-venv
  

• Run debugger without pytest:

    python -m {pdb|pudb.run} my-script.py
  

Reference:

• Python cryptography: https://cryptography.io/en/latest/

• Python virtualenv: https://virtualenv.pypa.io/en/latest/userguide/

• XOR on bytes: http://stackoverflow.com/questions/29408173/byte-operations-xor-in-python

• Python2.7 Unicode: https://fedorahosted.org/releases/k/i/kitchen/docs/unicode-frustrations.html

• Python2.7 String Literal: https://docs.python.org/2.7/reference/lexical_analysis.html#string-literals

Known Issues

Error installing Python cryptography library:

    sudo apt-get install build-essential libssl-dev libffi-dev python-dev

pytest does not show stdout if test passed:

Solution: add -s argument

pytest and py.test behave inconsistenly:

pytest is from logilab-common instead of Python: http://www.christianlong.com/blog/pytest-vs-pytest.html#the-problem

Solution: sudo apt-get autoremove python-logilab-common