COPYRIGHT

Copyright and licensing of the Python Cryptography Toolkit ("PyCrypto"):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Previously, the copyright and/or licensing status of the Python
Cryptography Toolkit ("PyCrypto") had been somewhat ambiguous.  The
original intention of Andrew M. Kuchling and other contributors has
been to dedicate PyCrypto to the public domain, but that intention was
not necessarily made clear in the original disclaimer (see
LEGAL/copy/LICENSE.orig).

Additionally, some files within PyCrypto had specified their own
licenses that differed from the PyCrypto license itself.  For example,
the original RIPEMD.c module simply had a copyright statement and
warranty disclaimer, without clearly specifying any license terms.
(An updated version on the author's website came with a license that
contained a GPL-incompatible advertising clause.)

To rectify this situation for PyCrypto 2.1, the following steps have
been taken:

 1. Obtaining explicit permission from the original contributors to
    dedicate their contributions to the public domain if they have not
    already done so.  (See the "LEGAL/copy/stmts" directory for
    contributors' statements.)

 2. Replacing some modules with clearly-licensed code from other
    sources (e.g. the DES and DES3 modules were replaced with new ones
    based on Tom St. Denis's public-domain LibTomCrypt library.)

 3. Replacing some modules with code written from scratch (e.g. the
    RIPEMD and Blowfish modules were re-implemented from their
    respective algorithm specifications without reference to the old
    implementations).

 4. Removing some modules altogether without replacing them.

To the best of our knowledge, with the exceptions noted below or
within the files themselves, the files that constitute PyCrypto are in
the public domain.  Most are distributed with the following notice:

  The contents of this file are dedicated to the public domain.  To
  the extent that dedication to the public domain is not available,
  everyone is granted a worldwide, perpetual, royalty-free,
  non-exclusive license to exercise all rights associated with the
  contents of this file for any purpose whatsoever.
  No rights are reserved.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.

Exceptions:

 - Portions of HMAC.py and setup.py are derived from Python 2.2, and
   are therefore Copyright (c) 2001, 2002, 2003 Python Software
   Foundation (All Rights Reserved).  They are licensed by the PSF
   under the terms of the Python 2.2 license.  (See the file
   LEGAL/copy/LICENSE.python-2.2 for details.)

 - The various GNU autotools (autoconf, automake, aclocal, etc.) are
   used during the build process.  This includes macros from
   autoconf-archive, which are located in the m4/ directory.  As is
   customary, some files from the GNU autotools are included in the
   source tree (in the root directory, and in the build-aux/
   directory).  These files are merely part of the build process, and
   are not included in binary builds of the software.

EXPORT RESTRICTIONS:

Note that the export or re-export of cryptographic software and/or
source code may be subject to regulation in your jurisdiction.