168 lines
5.7 KiB
Python
168 lines
5.7 KiB
Python
# -*- coding: utf-8 -*-
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#
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# ===================================================================
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# The contents of this file are dedicated to the public domain. To
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# the extent that dedication to the public domain is not available,
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# everyone is granted a worldwide, perpetual, royalty-free,
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# non-exclusive license to exercise all rights associated with the
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# contents of this file for any purpose whatsoever.
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# No rights are reserved.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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# ===================================================================
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"""SHA-3/512 cryptographic hash algorithm.
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SHA-3/512 belongs to the SHA-3 family of cryptographic hashes, as specified
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in `FIPS 202`__.
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The hash function produces the 512 bit digest of a message.
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>>> from Crypto.Hash import SHA3_512
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>>>
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>>> h_obj = SHA3_512.new()
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>>> h_obj.update(b'Some data')
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>>> print h_obj.hexdigest()
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.. __: http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf
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"""
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from Crypto.Util.py3compat import bord
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from Crypto.Util._raw_api import (load_pycryptodome_raw_lib,
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VoidPointer, SmartPointer,
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create_string_buffer,
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get_raw_buffer, c_size_t,
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expect_byte_string)
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from Crypto.Hash.keccak import _raw_keccak_lib
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class SHA3_512_Hash(object):
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"""Class that implements a SHA-3/512 hash
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"""
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#: The size of the resulting hash in bytes.
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digest_size = 64
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#: ASN.1 Object ID
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oid = "2.16.840.1.101.3.4.2.10"
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def __init__(self, data, update_after_digest):
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self._update_after_digest = update_after_digest
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self._digest_done = False
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state = VoidPointer()
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result = _raw_keccak_lib.keccak_init(state.address_of(),
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c_size_t(self.digest_size * 2),
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0x06)
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if result:
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raise ValueError("Error %d while instantiating SHA-3/512"
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% result)
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self._state = SmartPointer(state.get(),
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_raw_keccak_lib.keccak_destroy)
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if data:
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self.update(data)
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def update(self, data):
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"""Continue hashing of a message by consuming the next chunk of data.
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Repeated calls are equivalent to a single call with the concatenation
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of all the arguments. In other words:
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>>> m.update(a); m.update(b)
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is equivalent to:
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>>> m.update(a+b)
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:Parameters:
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data : byte string
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The next chunk of the message being hashed.
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"""
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if self._digest_done and not self._update_after_digest:
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raise TypeError("You can only call 'digest' or 'hexdigest' on this object")
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expect_byte_string(data)
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result = _raw_keccak_lib.keccak_absorb(self._state.get(),
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data,
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c_size_t(len(data)))
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if result:
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raise ValueError("Error %d while updating SHA-3/512"
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% result)
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return self
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def digest(self):
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"""Return the **binary** (non-printable) digest of the message that has been hashed so far.
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You cannot update the hash anymore after the first call to ``digest``
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(or ``hexdigest``).
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:Return: A byte string of `digest_size` bytes. It may contain non-ASCII
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characters, including null bytes.
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"""
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self._digest_done = True
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bfr = create_string_buffer(self.digest_size)
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result = _raw_keccak_lib.keccak_digest(self._state.get(),
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bfr,
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c_size_t(self.digest_size))
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if result:
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raise ValueError("Error %d while instantiating SHA-3/512"
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% result)
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self._digest_value = get_raw_buffer(bfr)
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return self._digest_value
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def hexdigest(self):
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"""Return the **printable** digest of the message that has been hashed so far.
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This method does not change the state of the hash object.
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:Return: A string of 2* `digest_size` characters. It contains only
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hexadecimal ASCII digits.
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"""
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return "".join(["%02x" % bord(x) for x in self.digest()])
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def new(self):
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return type(self)(None, self._update_after_digest)
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def new(*args, **kwargs):
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"""Return a fresh instance of the hash object.
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:Keywords:
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data : byte string
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Optional. The very first chunk of the message to hash.
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It is equivalent to an early call to ``update()``.
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update_after_digest : boolean
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Optional. By default, a hash object cannot be updated anymore after
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the digest is computed. When this flag is ``True``, such check
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is no longer enforced.
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:Return: A `SHA3_512_Hash` object
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"""
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data = kwargs.pop("data", None)
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update_after_digest = kwargs.pop("update_after_digest", False)
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if len(args) == 1:
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if data:
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raise ValueError("Initial data for hash specified twice")
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data = args[0]
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if kwargs:
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raise TypeError("Unknown parameters: " + str(kwargs))
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return SHA3_512_Hash(data, update_after_digest)
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#: The size of the resulting hash in bytes.
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digest_size = SHA3_512_Hash.digest_size
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