bran 0.4.0

Description:

bran 0.4.0

Bran provides transcoders for ASN.1
serialization and deserialization, and DER-encoding.
The purpose is to provide a serialization format for native Python types,
such as nested dicts, whose serialization is unambiguous and stable. That
is two values with the same contents serialize to the same byte string.
That makes it possible to create hashes and MACs to verify message
integrity.
Note that this does not make this package a full implementation of ASN.1
specs. That is not the goal. The goal is just to have a stable byte
representation of Python values; DER in particular is only picked because
it helps in this.

Usage
Code
You just encode some values. In most cases, you’ll want to use the DERTranscoder
class.
test = { 'some': { 'nested': 42, 'value': (0, 1, False) } }

from bran import DERTranscoder
transcoder = DERTranscoder()

encoded = transcoder.encode(test)
decoded = transcoder.decode(encoded)

assert decoded == test
In order for bran to be this simple to use, some assumptions are made. The
one with the most impact is that any collections.Mapping will be encoded
to the same byte representation, which means when decoded, it will become a
Python dict. Similar assumptions are made for collections.Set
and collections.Sequence.
For the purpose of hashing, consider the following code:
from bran.hash import hasher

test = { 'some': { 'nested': 42, 'value': (0, 1, False) } }

h = hasher()
h.update(test)
print(h.hexdigest()) # yields SHA512 hash of the DER serialized test

import hashlib
h = hasher(hashfunc = hashlib.md5)
h.update(test)
print(h.hexdigest()) # yields MD5 hash of the DER serialized test


Contributing
See CONTRIBUTING.md for details.


License
Licensed under MITNFA (MIT +no-false-attribs) License. See the
LICENSE.txt file for details.