Replace pycrypto by cryptography
https://github.com/pycrypto/pycrypto/issues/302 indicates one should replace pycrypto by the cryptography
library https://github.com/pyca/cryptography
https://github.com/pycrypto/pycrypto/issues/302 indicates one should replace pycrypto by the cryptography
library https://github.com/pyca/cryptography