.. module:: hashlib
   :synopsis: hashing algorithms

|see_cpython_module| :mod:`cpython:hashlib`.

This module implements binary data hashing algorithms. The exact inventory of available algorithms depends on a board. Among the algorithms which may be implemented:

• SHA256 - The current generation, modern hashing algorithm (of SHA2 series). It is suitable for cryptographically-secure purposes. Included in the MicroPython core and any board is recommended to provide this, unless it has particular code size constraints.
• SHA1 - A previous generation algorithm. Not recommended for new usages, but SHA1 is a part of number of Internet standards and existing applications, so boards targeting network connectivity and interoperatiability will try to provide this.
• MD5 - A legacy algorithm, not considered cryptographically secure. Only selected boards, targeting interoperatibility with legacy applications, will offer this.

Create an SHA256 hasher object and optionally feed data into it.

Create an SHA1 hasher object and optionally feed data into it.

Create an MD5 hasher object and optionally feed data into it.

.. method:: hash.update(data)

   Feed more binary data into hash.

.. method:: hash.digest()

   Return hash for all data passed through hash, as a bytes object. After this
   method is called, more data cannot be fed into the hash any longer.

.. method:: hash.hexdigest()

   This method is NOT implemented. Use ``binascii.hexlify(hash.digest())``
   to achieve a similar effect.