:mod:`viz.memo`
===============

.. py:module:: viz.memo


Module Contents
---------------

.. py:class:: Memo

   Bases: :class:`graphenecommon.memo.Memo`

   .. autoapi-inheritance-diagram:: viz.memo.Memo
      :parts: 1
:private-bases:
   Deals with Memos that are attached to a transfer.

   :param viz.account.Account from_account: Account that has sent
       the memo
   :param viz.account.Account to_account: Account that has received
       the memo
   :param viz.viz.Client blockchain_instance: Client
       instance

   A memo is encrypted with a shared secret derived from a private key of
   the sender and a public key of the receiver. Due to the underlying
   mathematics, the same shared secret can be derived by the private key
   of the receiver and the public key of the sender. The encrypted message
   is perturbed by a nonce that is part of the transmitted message.

   .. code-block:: python

       from viz.memo import Memo
       m = Memo("alice", "bob")
       m.unlock_wallet("secret")
       enc = (m.encrypt("foobar"))
       print(enc)
       print(m.decrypt(enc))
       >> foobar

   To decrypt a memo, simply use

   .. code-block:: python

       from viz.memo import Memo
       m = Memo()
       m.blockchain.wallet.unlock("secret")
       print(memo.decrypt(op_data["memo"]))

   if ``op_data`` being the payload of a transfer operation.

   .. method:: define_classes(self)



   .. method:: encrypt(self, message: str)


      Encrypt a memo.

      This class overriden because upstream assumes memo key is in
      account['options']['memo_key'], and bitshares memo format is different. We're using Golos memo format.

      :param str message: clear text memo message
      :returns: encrypted message
      :rtype: str


   .. method:: decrypt(self, message: str)


      Decrypt a message.

      :param dict message: encrypted memo message
      :returns: decrypted message
      :rtype: str