cSHAKE256.py 2.2 KB

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  1. # ===================================================================
  2. #
  3. # Copyright (c) 2021, Legrandin <helderijs@gmail.com>
  4. # All rights reserved.
  5. #
  6. # Redistribution and use in source and binary forms, with or without
  7. # modification, are permitted provided that the following conditions
  8. # are met:
  9. #
  10. # 1. Redistributions of source code must retain the above copyright
  11. # notice, this list of conditions and the following disclaimer.
  12. # 2. Redistributions in binary form must reproduce the above copyright
  13. # notice, this list of conditions and the following disclaimer in
  14. # the documentation and/or other materials provided with the
  15. # distribution.
  16. #
  17. # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  18. # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  19. # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  20. # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  21. # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  22. # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  23. # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  24. # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  25. # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26. # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  27. # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28. # POSSIBILITY OF SUCH DAMAGE.
  29. # ===================================================================
  30. from Crypto.Util._raw_api import c_size_t
  31. from Crypto.Hash.cSHAKE128 import cSHAKE_XOF
  32. def _new(data, custom, function):
  33. # Use Keccak[512]
  34. return cSHAKE_XOF(data, custom, 512, function)
  35. def new(data=None, custom=None):
  36. """Return a fresh instance of a cSHAKE256 object.
  37. Args:
  38. data (bytes/bytearray/memoryview):
  39. The very first chunk of the message to hash.
  40. It is equivalent to an early call to :meth:`update`.
  41. Optional.
  42. custom (bytes):
  43. Optional.
  44. A customization bytestring (``S`` in SP 800-185).
  45. :Return: A :class:`cSHAKE_XOF` object
  46. """
  47. # Use Keccak[512]
  48. return cSHAKE_XOF(data, custom, 512, b'')