spectral-aead 0.0.5
An algorithm for authenticated encryption with associated data using Speck and HMAC-SHA256.
License: BSD

Spectral AEAD
=============

Spectral is algorithm for authenticated encryption with associated data;
it uses
`Speck <https://csrc.nist.gov/csrc/media/events/lightweight-cryptography-workshop-2015/documents/papers/session1-shors-paper.pdf>`__
in `CTR
mode <https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38a.pdf>`__
as the underlying cipher (with a 128-bit block size and a 128-bit key
size) along with
`HMAC <https://nvlpubs.nist.gov/nistpubs/fips/nist.fips.198-1.pdf>`__-`SHA256 <https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf>`__
in an `Encrypt-then-MAC <https://www.iso.org/standard/46345.html>`__
construction.

This package provides tested, performant **Python 3** CFFI bindings to
an implementation of Spectral, including abstractions for simplified
encryption and decryption.

Installation
============

You can install this package using ``pip`` or the included ``setup.py``
script:

::

   # Using pip
   pip install spectral-aead

   # Using setup.py
   python setup.py install

Usage
=====

.. code:: python

   from spectral import *

   # Demonstration key, nonce, plaintext and associated data
   key = b"\0" * spectral.KEY_SIZE
   nonce = b"\0" * spectral.NONCE_SIZE
   plaintext = b"\0" * 16
   associated = b"\0" * 16

   # Spectral simplified encryption
   encrypted = encrypt(key, plaintext, associated)  # Associated data is optional

   # Spectral simplified decryption
   computed_plaintext = decrypt(key, encrypted, associated)  # Raises RuntimeError if any parameter has been tampered with
   assert plaintext == computed_plaintext

   # Spectral disjoint encryption
   ciphertext, mac = encrypt_disjoint(key, nonce, plaintext, associated)  # Associated data is optional

   # Spectral disjoint decryption
   computed_plaintext = decrypt_disjoint(key, nonce, ciphertext, mac, associated)  # Raises RuntimeError if any parameter has been tampered with
   assert plaintext == computed_plaintext

License
=======

.. code:: text

   BSD 3-Clause License

   Copyright (c) 2018, Phil Demetriou
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are met:

   * Redistributions of source code must retain the above copyright notice, this
     list of conditions and the following disclaimer.

   * Redistributions in binary form must reproduce the above copyright notice,
     this list of conditions and the following disclaimer in the documentation
     and/or other materials provided with the distribution.

   * Neither the name of the copyright holder nor the names of its
     contributors may be used to endorse or promote products derived from
     this software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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