Can not install the Python cryptography module

I have a python program with the line.

from cryptography.hazmat.backends import default_backend

When I run with python3, I get the error

ModuleNotFoundError: no module called & # 39; cryptography & # 39;

I installed python-pip, then I ran

pip install cryptography
pip install pycrypto

And I still have the same error. Any solution?