update to criptography library calls

[popliviustefan]

Updated the calls to the cryprography library to the newest version.

[banksy-git]

Hey, thanks for the PR. What does it fix / do?

[popliviustefan]

Hi! I tried to use the script to extract the password for an access point and the scipt gave some errors regarding the calls to cryptografic library. After a small investigation, I updated those calls and could use the script to gain access to the device.
So I thought I should share this info through this PR.
If you need the exact details, tell me and I will run the original script and tell you the error it gave.

[banksy-git]

Probably an update to cryptography.io would have worked too - see the docs here about backend :

• https://cryptography.io/en/latest/faq/#what-happened-to-the-backend-argument

We should have a Python environment setup section/script for that - reading the various threads it seems to be a common theme.