suggest to replace dead package pycypto with PyCryptodome

[hick]

as the issue in the github project pycypto : pycrypto/pycrypto#238

PyCrypto is dead. Switch to PyCryptodome (GitHub: https://github.com/Legrandin/pycryptodome PyPi: https://pypi.python.org/pypi/pycryptodome).

As you may or may not have noticed the last change to PyCrypto was made three years ago.