blake2.py -- version 1
This pure Python implementation of BLAKE2 supports both
BLAKE2b and BLAKE2s. It runs under both Python 2.7 and
Python 3.3. For information about the BLAKE2 algorithm
please see https://blake2.net
blake2.py differs from the structure of the C reference
version primarily by effecting classes (object orientation)
and certain optimizations in the area of compress() and
G(). The goal of these optimizations was to improve
performance, and while a gain of about 50% was attained,
this program is way too slow to be competitive with C
implementations. This program can be useful, however,
where a pure Python implementation is required, where the
data to be hashed is small, and, of course, for educational
purposes.
Credit is given to Dmitry Chestnykh <dmitry@codingrobots.com>
for his work defining a Python API for pyblake2 and his
excellent documentation of that interface. Please see
http://pythonhosted.org/pyblake2/
I have adoped much of Dmitry's API and many of his data
names. Here are a few known differences between blake2.py
and pyblake2.
- capitalization of BLAKE2b and BLAKE2s class names
- digest() is an alias for final()
- under Python 2.7 the returned digest is a str; under
Python 3.3 the digest is a bytes object. Neither is
a pyblake2 hash object.
- hexdigest() returns a str under Pythons 2.7 and 3.3
- http://pythonhosted.org/pyblake2/module.html#pyblake2.hash.digest
says "Return the digest of the data so far" which
implies hashing may be resumed after a digest is
retrieved at some arbitrary interim point. What really
happens is that when final() is called, padding is
added (if needed), and a final compress is performed on
the last block. An intermediate digest value will NOT
include a residual value left in the buffer (unless you
just happen to be on an exact multiple of BLOCKSIZE).
IMO, to resume hashing after "closing out" the state
should NOT be permitted, hence blake2.py will throw an
exception if resumption is attempted.
Arguably, a better approach would be to make a deepcopy
by calling copy() and then call digest() or hexdigest()
on the copy, and resume hashing on the original.
- digest() and hexdigest() may be called multiple times
when finished hashing. Each calls final(), but final()
performs the final compression only once.
Other notes:
- All data, key, salt, and person inputs are big endian
bytes, NOT strings. Likewise, the final digest is
big endian bytes.
- blake2.py has been tested in sequential and tree modes;
it has NOT been tested in parallel mode.
- blake2.py is NOT a secure implementation. For example,
keys are not securely overwritten after use. Use this
implementation on a presumably secure platform only.
Simple usage example:
import blake2
digest = blake2.BLAKE2b(b'hello world').digest()
Another, generating a 20-byte digest (in hex):
from blake2 import BLAKE2b
data1 = b'hello '
data2 = b'world'
b2 = BLAKE2b(digest_size=20)
b2.update(data1)
b2.update(data2)
hexdigest = b2.hexdigest()
-----
"miniServer" BLAKE2b thruput (OSX 2.53GHz Core2Duo):
MiB/sec
0.22 python 2.7, blake2.py v1
0.36 python 3.3, blake2.py v1
0.60 pypy 2.2 (python 2.7), blake2.py v1
0.35 python 2.7, cythonized blake2.py v1
0.59 python 3.3, cythonized blake2.py v1
1.99 python 2.7, cython + some cdef unsigned long long
>>> 301.01 python 2.7, Dmitry's pyblake2 wrapper <<<
"godspeed" BLAKE2b thruput (Ubuntu 12.4LTS 4.4GHz i5-3570K):
MiB/sec
0.72 python 2.7, blake2.py v1
0.84 python 3.2, blake2.py v1
0.96 pypy 2.2 (python 2.7), blake2.py v1
...still [very] slow. :-/
Consider using blake2.py when you need a pure Python
implementation, and convert to Dmitry's pyblake2, with
hopefully minimum effort, when more speed is required.
-----
License:
Copyright (c) 2009-2018 Larry Bugbee, Kent, WA, USA
Permission to use, copy, modify, and/or distribute this software
for any purpose with or without fee is hereby granted, provided
that the above copyright notice and this permission notice appear
in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
(the ISC license, a minor tweak of the BSD license)
Enjoy,
Larry Bugbee
December 2013
rev Mar 2014, Mar 2018
PS: If you are interested in a 100% Python implementation of the
original BLAKE hash algorithm, predecessor to BLAKE2, submitted
to and a finalist in the NIST SHA3 competition, go to:
http://www.seanet.com/~bugbee/crypto/blake/