mirror of
https://gitlab.gnome.org/GNOME/libsecret.git
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86 lines
2.8 KiB
Python
86 lines
2.8 KiB
Python
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# Upstream Author: Zooko O'Whielacronx <zooko@zooko.com>
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#
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# Copyright:
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#
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# You may use this package under the GNU General Public License, version
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# 2 or, at your option, any later version. You may use this package
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# under the Transitive Grace Period Public Licence, version 1.0 or, at
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# your option, any later version. (You may choose to use this package
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# under the terms of either licence, at your option.) See the file
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# COPYING.GPL for the terms of the GNU General Public License, version 2.
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# See the file COPYING.TGPPL.html for the terms of the Transitive Grace
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# Period Public Licence, version 1.0.
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#
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# The following licensing text applies to a subset of the Crypto++ source code
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# which is included in the pycryptopp source tree under the "embeddedcryptopp"
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# subdirectory. That embedded subset of the Crypto++ source code is not used
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# when pycryptopp is built for Debian -- instead the --disable-embedded-cryptopp
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# option to "setup.py build" is used to for pycryptopp to build against the
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# system libcryptopp.
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import hashlib, hmac
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import math
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from binascii import a2b_hex, b2a_hex
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class HKDF(object):
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def __init__(self, ikm, L, salt=None, info="", digestmod = None):
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self.ikm = ikm
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self.keylen = L
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if digestmod is None:
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digestmod = hashlib.sha256
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if callable(digestmod):
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self.digest_cons = digestmod
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else:
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self.digest_cons = lambda d='':digestmod.new(d)
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self.hashlen = len(self.digest_cons().digest())
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if salt is None:
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self.salt = chr(0)*(self.hashlen)
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else:
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self.salt = salt
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self.info = info
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#extract PRK
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def extract(self):
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h = hmac.new(self.salt, self.ikm, self.digest_cons)
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self.prk = h.digest()
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return self.prk
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#expand PRK
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def expand(self):
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N = math.ceil(float(self.keylen)/self.hashlen)
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T = ""
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temp = ""
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i=0x01
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'''while len(T)<2*self.keylen :
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msg = temp
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msg += self.info
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msg += b2a_hex(chr(i))
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h = hmac.new(self.prk, a2b_hex(msg), self.digest_cons)
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temp = b2a_hex(h.digest())
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i += 1
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T += temp
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'''
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while len(T)<self.keylen :
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msg = temp
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msg += self.info
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msg += chr(i)
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h = hmac.new(self.prk, msg, self.digest_cons)
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temp = h.digest()
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i += 1
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T += temp
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self.okm = T[0:self.keylen]
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return self.okm
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def new(ikm, L, salt=None, info="", digestmod = None):
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return HKDF(ikm, L,salt,info,digestmod)
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def hkdf(ikm, length, salt=None, info=""):
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hk = HKDF(ikm, length ,salt,info)
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computedprk = hk.extract()
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return hk.expand() |