Investigate replacement of pyotp with equivalent functionality in cryptography

[rmol]

Description

The cryptography package contains support for HOTP/TOTP. We should see if it can do everything we use pyotp for. Those two packages are excellent and maintained, but our update protocol is laborious enough that we should eliminate any dependencies we can.

Edited by @eloquence to reflect removal of scrypt dependency, 2021-09-28

[evilaliv3]

@rmol : Actually i come to this evaluation myself within @globaleaks and i just made this change.

Here you can find the code i used to reimplement TOTP by means of python-cryptography: globaleaks/GlobaLeaks@64750f4

[rmol]

Hey, thanks @evilaliv3! That should save us some time. 🙂

[nabla-c0d3]

The dependency to scrypt was removed in #5694.

[eloquence]

Thanks, retitled accordingly!

[nabla-c0d3]

PR at #6679 is ready

[nabla-c0d3]

PR #6679 was merged so this issue can be closed 👍