pycryptodome/lib/Crypto/Hash/SHA3_512.py

# -*- coding: utf-8 -*-
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"""SHA-3/512 cryptographic hash algorithm.

SHA-3/512 belongs to the SHA-3 family of cryptographic hashes, as specified
in `FIPS 202`__.

The hash function produces the 512 bit digest of a message.

    >>> from Crypto.Hash import SHA3_512
    >>>
    >>> h_obj = SHA3_512.new()
    >>> h_obj.update(b'Some data')
    >>> print h_obj.hexdigest()

.. __: http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf
"""

from Crypto.Util.py3compat import bord

from Crypto.Util._raw_api import (load_pycryptodome_raw_lib,
                                  VoidPointer, SmartPointer,
                                  create_string_buffer,
                                  get_raw_buffer, c_size_t,
                                  expect_byte_string)

from Crypto.Hash.keccak import _raw_keccak_lib

class SHA3_512_Hash(object):
    """Class that implements a SHA-3/512 hash
    """

    #: The size of the resulting hash in bytes.
    digest_size = 64

    #: ASN.1 Object ID
    oid = "2.16.840.1.101.3.4.2.10"

    def __init__(self, data=None):
        state = VoidPointer()
        result = _raw_keccak_lib.keccak_init(state.address_of(),
                                             c_size_t(self.digest_size),
                                             0x06)
        if result:
            raise ValueError("Error %d while instantiating SHA-3/512"
                             % result)
        self._state = SmartPointer(state.get(),
                                   _raw_keccak_lib.keccak_destroy)
        if data:
            self.update(data)

    def update(self, data):
        """Continue hashing of a message by consuming the next chunk of data.

        Repeated calls are equivalent to a single call with the concatenation
        of all the arguments. In other words:

           >>> m.update(a); m.update(b)

        is equivalent to:

           >>> m.update(a+b)

        :Parameters:
          data : byte string
            The next chunk of the message being hashed.
        """

        expect_byte_string(data)
        result = _raw_keccak_lib.keccak_absorb(self._state.get(),
                                               data,
                                               c_size_t(len(data)))
        if result:
            raise ValueError("Error %d while instantiating SHA-3/512"
                             % result)

    def digest(self):
        """Return the **binary** (non-printable) digest of the message that has been hashed so far.

        This method does not change the state of the hash object.
        You can continue updating the object after calling this function.

        :Return: A byte string of `digest_size` bytes. It may contain non-ASCII
         characters, including null bytes.
        """

        bfr = create_string_buffer(self.digest_size)
        result = _raw_keccak_lib.keccak_digest(self._state.get(),
                                               bfr,
                                               c_size_t(self.digest_size))
        if result:
            raise ValueError("Error %d while instantiating SHA-3/512"
                             % result)

        return get_raw_buffer(bfr)

    def hexdigest(self):
        """Return the **printable** digest of the message that has been hashed so far.

        This method does not change the state of the hash object.

        :Return: A string of 2* `digest_size` characters. It contains only
         hexadecimal ASCII digits.
        """

        return "".join(["%02x" % bord(x) for x in self.digest()])

    def copy(self):
        """Return a copy ("clone") of the hash object.

        The copy will have the same internal state as the original hash
        object.
        This can be used to efficiently compute the digests of strings that
        share a common initial substring.

        :Return: A hash object of the same type
        """

        clone = type(self)()
        result = _raw_keccak_lib.keccak_copy(self._state.get(),
                                             clone._state.get())
        if result:
            raise ValueError("Error %d while copying SHA-3/512" % result)
        return clone

    def new(self, data=None):
        return type(self)(data=data)


def new(data=None):
    """Return a fresh instance of the hash object.

    :Parameters:
       data : byte string
        The very first chunk of the message to hash.
        It is equivalent to an early call to ``update()``.
        Optional.

    :Return: A `SHA3_512_Hash` object
    """
    return SHA3_512_Hash(data=data)

#: The size of the resulting hash in bytes.
digest_size = SHA3_512_Hash.digest_size