Crypto Project
==============
This code was written for educational purposes and to experiment with some of
Google's public source code, mainly protobuf, gtest and gflags.  It may also
be incorporated into Cloudproxy at some point after I do more testing but
maybe not. [2020: not.  Cloudproxy uses the GO crypto library]

License
-------
Except as expressly set forth in particular files, all files in this project are
licensed under the Apache 2.0 license, a copy of which is in this main directory
in the file LICENSE-2.0.txt.


Pre-existing code license incorporated in this project
------------------------------------------------------
Tinyxml (in the xml subdirectory) [No longer used]
Downloaded from https://github.com/leethomason/tinyxml2
http://www.grinninglizard.com/tinyxml2/ on September 4, 2014 
Original author:
License granted by original authors retained in files (tinyxml2 is not
currently compiled or linked into the code).

Sha1, sha256
Downloaded from 
http://sourceforge.net/projects/cryptopp/files/cryptopp/5.6.2/cryptopp562.zip
on September 4, 2014 
Original author: Wei Dai
License granted by original authors:
  Steve Reid implemented SHA-1. Wei Dai implemented SHA-2.
  Both are in the public domain.

Aes
Downloaded from 
ftp://ftp.aci.com.pl/pub/security/cryptography/algorithms/aes/aes-c-rijmen
on September 4, 2014 
Original authors:
    Vincent Rijmen <[email protected]>
    Antoon Bosselaers <[email protected]>
    Paulo Barreto <[email protected]>
License from original authors
    All code contained in this distributed is placed in the public domain.

    Disclaimer:

    THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS 
    OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
    ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE 
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 
    BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
    WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
    OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
    EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

Protobuf sample code from the protobuf-2.5.0 public distribution.
Gtest sample code from the gtest-1.7.0 public distribution.
Original licenses:
   Copyright 2008, Google Inc.
   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 Google Inc. 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 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Simple Twofish by Niels Ferguson
License
   Fast, portable, and easy-to-use Twofish implementation,
   Version 0.3.
   Copyright (c) 2002 by Niels Ferguson.
   The author hereby grants a perpetual license to everybody to
   use this code for any purpose as long as the copyright message is included
   in the source code of this or any derived work.
   Yes, this means that you, your company, your club, and anyone else
   can use this code anywhere you want. You can change it and distribute it
   under the GPL, include it in your commercial product without releasing
   the source code, put it on the web, etc.


Timing attacks
--------------
  This code is not meant to be resistant to timing attacks.  In fact,
  it is extremely not timing attack resistant.  To make it resistant requires 
  changing all the calculations be fixed length and "if-free".  So my advice
  in not to use it for on-line encryption/decryption without extensive changes.

How to build
------------
  For v1, the command buildall in the root directory builds all the code once you set up
  directories for the object files and binaries.  I put binaries in ~/cryptobin and
  object files in ~/cryptoobj (in several subdirectories).  Most of the executables
  buildall builds are tests; however, there is a command line utility called cryptutil.
  In v2, make_all_tests.sh builds everything.

  You need a c-11 compiler with the standard libraries, protobuf, gtest and gflags all
  of which are available in open source.  Currently, the code is Intel64 only (the
  assembly assist assumes Intel64 and RNG and aes use Ivy Bridge and later instructions
  for aesni and RNG).

Feedback
--------
  I welcome corrections and suggestions.  Please do not send material that you are not
  authorized to send.  All feedback will be treated as licensed under the same terms
  as this code; so don't send any information or feedback that you cannot or do
  not wish to license under those terms.

Version 2
---------
  In September, 2020, I rewrote most of the cryptocode to be cleaner and align
  with my current C++ coding style. The new version is in v2.  I also added LLL
  and some lattice based crypto.  The original version remains in the v1
  directory.  I've also done an ARM 64-bit version of the software.  There are
  now no dependencies on any serialization except protobuf.  Same license
  conditions apply.


John
[email protected]