303 lines
7.8 KiB
Python
303 lines
7.8 KiB
Python
# hashes.py
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#
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# Copyright (C) 2006-2016 wolfSSL Inc.
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#
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# This file is part of wolfSSL. (formerly known as CyaSSL)
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#
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# wolfSSL is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# wolfSSL is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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from wolfcrypt._ffi import ffi as _ffi
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from wolfcrypt._ffi import lib as _lib
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from wolfcrypt.utils import t2b, b2h
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from wolfcrypt.exceptions import *
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class _Hash(object):
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"""
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A **PEP 247: Cryptographic Hash Functions** compliant
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**Hash Function Interface**.
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"""
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def __init__(self, string=None):
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self._native_object = _ffi.new(self._native_type)
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ret = self._init()
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if ret < 0:
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raise WolfCryptError("Hash init error (%d)" % ret)
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if (string):
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self.update(string)
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@classmethod
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def new(cls, string=None):
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"""
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Creates a new hashing object and returns it. The optional
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**string** parameter, if supplied, will be immediately
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hashed into the object's starting state, as if
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obj.update(string) was called.
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"""
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return cls(string)
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def copy(self):
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"""
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Returns a separate copy of this hashing object. An update
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to this copy won't affect the original object.
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"""
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copy = self.new("")
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_ffi.memmove(copy._native_object,
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self._native_object,
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self._native_size)
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return copy
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def update(self, string):
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"""
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Hashes **string** into the current state of the hashing
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object. update() can be called any number of times during
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a hashing object's lifetime.
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"""
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string = t2b(string)
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ret = self._update(string)
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if ret < 0:
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raise WolfCryptError("Hash update error (%d)" % ret)
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def digest(self):
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"""
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Returns the hash value of this hashing object as a string
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containing 8-bit data. The object is not altered in any
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way by this function; you can continue updating the object
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after calling this function.
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"""
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result = t2b("\0" * self.digest_size)
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if self._native_object:
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obj = _ffi.new(self._native_type)
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_ffi.memmove(obj, self._native_object, self._native_size)
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ret = self._final(obj, result)
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if ret < 0:
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raise WolfCryptError("Hash finalize error (%d)" % ret)
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return result
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def hexdigest(self):
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"""
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Returns the hash value of this hashing object as a string
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containing hexadecimal digits. Lowercase letters are used
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for the digits 'a' through 'f'. Like the .digest() method,
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this method doesn't alter the object.
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"""
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return b2h(self.digest())
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class Sha(_Hash):
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"""
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**SHA-1** is a cryptographic hash function standardized by **NIST**.
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It produces an [ **160-bit | 20 bytes** ] message digest.
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"""
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digest_size = 20
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_native_type = "Sha *"
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_native_size = _ffi.sizeof("Sha")
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def _init(self):
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return _lib.wc_InitSha(self._native_object)
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def _update(self, data):
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return _lib.wc_ShaUpdate(self._native_object, data, len(data))
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def _final(self, obj, ret):
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return _lib.wc_ShaFinal(obj, ret)
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class Sha256(_Hash):
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"""
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**SHA-256** is a cryptographic hash function from the
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**SHA-2 family** and is standardized by **NIST**.
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It produces a [ **256-bit | 32 bytes** ] message digest.
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"""
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digest_size = 32
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_native_type = "Sha256 *"
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_native_size = _ffi.sizeof("Sha256")
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def _init(self):
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return _lib.wc_InitSha256(self._native_object)
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def _update(self, data):
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return _lib.wc_Sha256Update(self._native_object, data, len(data))
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def _final(self, obj, ret):
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return _lib.wc_Sha256Final(obj, ret)
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class Sha384(_Hash):
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"""
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**SHA-384** is a cryptographic hash function from the
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**SHA-2 family** and is standardized by **NIST**.
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It produces a [ **384-bit | 48 bytes** ] message digest.
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"""
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digest_size = 48
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_native_type = "Sha384 *"
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_native_size = _ffi.sizeof("Sha384")
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def _init(self):
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return _lib.wc_InitSha384(self._native_object)
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def _update(self, data):
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return _lib.wc_Sha384Update(self._native_object, data, len(data))
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def _final(self, obj, ret):
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return _lib.wc_Sha384Final(obj, ret)
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class Sha512(_Hash):
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"""
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**SHA-512** is a cryptographic hash function from the
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**SHA-2 family** and is standardized by **NIST**.
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It produces a [ **512-bit | 64 bytes** ] message digest.
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"""
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digest_size = 64
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_native_type = "Sha512 *"
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_native_size = _ffi.sizeof("Sha512")
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def _init(self):
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return _lib.wc_InitSha512(self._native_object)
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def _update(self, data):
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return _lib.wc_Sha512Update(self._native_object, data, len(data))
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def _final(self, obj, ret):
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return _lib.wc_Sha512Final(obj, ret)
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# Hmac types
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_TYPE_SHA = 1
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_TYPE_SHA256 = 2
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_TYPE_SHA384 = 5
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_TYPE_SHA512 = 4
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_HMAC_TYPES = [_TYPE_SHA, _TYPE_SHA256, _TYPE_SHA384, _TYPE_SHA512]
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class _Hmac(_Hash):
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"""
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A **PEP 247: Cryptographic Hash Functions** compliant
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**Keyed Hash Function Interface**.
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"""
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digest_size = None
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_native_type = "Hmac *"
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_native_size = _ffi.sizeof("Hmac")
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def __init__(self, key, string=None):
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key = t2b(key)
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self._native_object = _ffi.new(self._native_type)
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ret = self._init(self._type, key)
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if ret < 0:
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raise WolfCryptError("Hmac init error (%d)" % ret)
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if (string):
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self.update(string)
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@classmethod
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def new(cls, key, string=None):
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"""
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Creates a new hashing object and returns it. **key** is
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a required parameter containing a string giving the key
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to use. The optional **string** parameter, if supplied,
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will be immediately hashed into the object's starting
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state, as if obj.update(string) was called.
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"""
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return cls(key, string)
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def _init(self, type, key):
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return _lib.wc_HmacSetKey(self._native_object, type, key, len(key))
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def _update(self, data):
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return _lib.wc_HmacUpdate(self._native_object, data, len(data))
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def _final(self, obj, ret):
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return _lib.wc_HmacFinal(obj, ret)
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class HmacSha(_Hmac):
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"""
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A HMAC function using **SHA-1** as it's cryptographic
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hash function.
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It produces a [ **512-bit | 64 bytes** ] message digest.
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"""
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_type = _TYPE_SHA
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digest_size = Sha.digest_size
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class HmacSha256(_Hmac):
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"""
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A HMAC function using **SHA-256** as it's cryptographic
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hash function.
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It produces a [ **512-bit | 64 bytes** ] message digest.
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"""
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_type = _TYPE_SHA256
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digest_size = Sha256.digest_size
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class HmacSha384(_Hmac):
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"""
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A HMAC function using **SHA-384** as it's cryptographic
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hash function.
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It produces a [ **512-bit | 64 bytes** ] message digest.
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"""
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_type = _TYPE_SHA384
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digest_size = Sha384.digest_size
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class HmacSha512(_Hmac):
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"""
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A HMAC function using **SHA-512** as it's cryptographic
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hash function.
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It produces a [ **512-bit | 64 bytes** ] message digest.
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"""
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_type = _TYPE_SHA512
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digest_size = Sha512.digest_size
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