import pgpy is failing with an error - cryptography.utils has no attribute register_interface

[pradeepravi87]

We started facing this issue in the Databricks notebook environment, we realized this is because of cryptography library was upgraded a few hours back.

This breaks the compatibility to use the recent version of pgpy in our environment

Stack Trace -

AttributeError: module 'cryptography.utils' has no attribute 'register_interface'

AttributeError Traceback (most recent call last)
in
----> 1 import pgpy

/databricks/python_shell/dbruntime/PythonPackageImportsInstrumentation/init.py in import_patch(name, globals, locals, fromlist, level)
165 # Import the desired module. If you’re seeing this while debugging a failed import,
166 # look at preceding stack frames for relevant error information.
--> 167 original_result = python_builtin_import(name, globals, locals, fromlist, level)
168
169 is_root_import = thread_local._nest_level == 1

/local_disk0/.ephemeral_nfs/envs/pythonEnv-4001c277-1e53-462b-91f8-060b1edfc8c6/lib/python3.8/site-packages/pgpy/init.py in
2 """
3
----> 4 from .pgp import PGPKey
5 from .pgp import PGPKeyring
6 from .pgp import PGPMessage

/databricks/python_shell/dbruntime/PythonPackageImportsInstrumentation/init.py in import_patch(name, globals, locals, fromlist, level)
165 # Import the desired module. If you’re seeing this while debugging a failed import,
166 # look at preceding stack frames for relevant error information.
--> 167 original_result = python_builtin_import(name, globals, locals, fromlist, level)
168
169 is_root_import = thread_local._nest_level == 1

/local_disk0/.ephemeral_nfs/envs/pythonEnv-4001c277-1e53-462b-91f8-060b1edfc8c6/lib/python3.8/site-packages/pgpy/pgp.py in
25 from cryptography.hazmat.primitives import hashes
26
---> 27 from .constants import CompressionAlgorithm
28 from .constants import Features
29 from .constants import HashAlgorithm

/databricks/python_shell/dbruntime/PythonPackageImportsInstrumentation/init.py in import_patch(name, globals, locals, fromlist, level)
165 # Import the desired module. If you’re seeing this while debugging a failed import,
166 # look at preceding stack frames for relevant error information.
--> 167 original_result = python_builtin_import(name, globals, locals, fromlist, level)
168
169 is_root_import = thread_local._nest_level == 1

/local_disk0/.ephemeral_nfs/envs/pythonEnv-4001c277-1e53-462b-91f8-060b1edfc8c6/lib/python3.8/site-packages/pgpy/constants.py in
21 from .decorators import classproperty
22 from .types import FlagEnum
---> 23 from ._curves import BrainpoolP256R1, BrainpoolP384R1, BrainpoolP512R1, X25519, Ed25519
24
25 all = ['Backend',

/databricks/python_shell/dbruntime/PythonPackageImportsInstrumentation/init.py in import_patch(name, globals, locals, fromlist, level)
165 # Import the desired module. If you’re seeing this while debugging a failed import,
166 # look at preceding stack frames for relevant error information.
--> 167 original_result = python_builtin_import(name, globals, locals, fromlist, level)
168
169 is_root_import = thread_local._nest_level == 1

/local_disk0/.ephemeral_nfs/envs/pythonEnv-4001c277-1e53-462b-91f8-060b1edfc8c6/lib/python3.8/site-packages/pgpy/_curves.py in
35
36
---> 37 @utils.register_interface(ec.EllipticCurve)
38 class BrainpoolP256R1(object):
39 name = 'brainpoolP256r1'

[mitgr81]

This looks to be the relevant change in cryptography: pyca/cryptography#7234

[hofrob]

Seeing the same issue after upgrading cryptography to V38.*

project/foo.py:9: in <module>
    import pgpy
venv/lib/python3.10/site-packages/pgpy/__init__.py:4: in <module>
    from .pgp import PGPKey
venv/lib/python3.10/site-packages/pgpy/pgp.py:27: in <module>
    from .constants import CompressionAlgorithm
venv/lib/python3.10/site-packages/pgpy/constants.py:23: in <module>
    from ._curves import BrainpoolP256R1, BrainpoolP384R1, BrainpoolP512R1, X25519, Ed25519
venv/lib/python3.10/site-packages/pgpy/_curves.py:37: in <module>
    @utils.register_interface(ec.EllipticCurve)
E   AttributeError: module 'cryptography.utils' has no attribute 'register_interface'

[swadeesh]

You can try the version 37.0. See the install log, pgpy is using version 37 which should fix your problem.

%pip install cryptography==37.0
%pip install PGPy

import pgpy

Python interpreter will be restarted.
Collecting cryptography==37.0
Downloading cryptography-37.0.0-cp36-abi3-manylinux_2_24_x86_64.whl (4.0 MB)
Requirement already satisfied: cffi>=1.12 in /databricks/python3/lib/python3.8/site-packages (from cryptography==37.0) (1.14.5)
Requirement already satisfied: pycparser in /databricks/python3/lib/python3.8/site-packages (from cffi>=1.12->cryptography==37.0) (2.20)
Installing collected packages: cryptography
Attempting uninstall: cryptography
Found existing installation: cryptography 38.0.1
Not uninstalling cryptography at /databricks/python3/lib/python3.8/site-packages, outside environment /local_disk0/.ephemeral_nfs/envs/pythonEnv-fcff4e9f-8cfa-4383-98ad-989b91570005
Can't uninstall 'cryptography'. No files were found to uninstall.
Successfully installed cryptography-37.0.0
Python interpreter will be restarted.
Python interpreter will be restarted.
Requirement already satisfied: PGPy in /databricks/python3/lib/python3.8/site-packages (0.5.4)
Requirement already satisfied: six>=1.9.0 in /databricks/python3/lib/python3.8/site-packages (from PGPy) (1.15.0)
Requirement already satisfied: cryptography>=2.6 in /local_disk0/.ephemeral_nfs/envs/pythonEnv-fcff4e9f-8cfa-4383-98ad-989b91570005/lib/python3.8/site-packages (from PGPy) (37.0.0)
Requirement already satisfied: pyasn1 in /databricks/python3/lib/python3.8/site-packages (from PGPy) (0.4.8)
Requirement already satisfied: cffi>=1.12 in /databricks/python3/lib/python3.8/site-packages (from cryptography>=2.6->PGPy) (1.14.5)
Requirement already satisfied: pycparser in /databricks/python3/lib/python3.8/site-packages (from cffi>=1.12->cryptography>=2.6->PGPy) (2.20)
Python interpreter will be restarted.

[vgopinathlal]

yes with cryptography==37.0.4 it works well..

[reaperhulk]

This can be fixed by switching from register_interface to subclassing (sigh) the ec.EllipticCurve abstract base class and will work in all versions of cryptography including 38.0. That will require a PR against this project + new release of course.

[hofrob]

I created a PR that does exactly what you proposed (and what they did internally in the cryptography library). I'm not sure if this is helpful though, since I have no idea what I'm doing 😬.

[pradeepravi87]

You can try the version 37.0. See the install log, pgpy is using version 37 which should fix your problem.

%pip install cryptography==37.0 %pip install PGPy

import pgpy

Python interpreter will be restarted. Collecting cryptography==37.0 Downloading cryptography-37.0.0-cp36-abi3-manylinux_2_24_x86_64.whl (4.0 MB) Requirement already satisfied: cffi>=1.12 in /databricks/python3/lib/python3.8/site-packages (from cryptography==37.0) (1.14.5) Requirement already satisfied: pycparser in /databricks/python3/lib/python3.8/site-packages (from cffi>=1.12->cryptography==37.0) (2.20) Installing collected packages: cryptography Attempting uninstall: cryptography Found existing installation: cryptography 38.0.1 Not uninstalling cryptography at /databricks/python3/lib/python3.8/site-packages, outside environment /local_disk0/.ephemeral_nfs/envs/pythonEnv-fcff4e9f-8cfa-4383-98ad-989b91570005 Can't uninstall 'cryptography'. No files were found to uninstall. Successfully installed cryptography-37.0.0 Python interpreter will be restarted. Python interpreter will be restarted. Requirement already satisfied: PGPy in /databricks/python3/lib/python3.8/site-packages (0.5.4) Requirement already satisfied: six>=1.9.0 in /databricks/python3/lib/python3.8/site-packages (from PGPy) (1.15.0) Requirement already satisfied: cryptography>=2.6 in /local_disk0/.ephemeral_nfs/envs/pythonEnv-fcff4e9f-8cfa-4383-98ad-989b91570005/lib/python3.8/site-packages (from PGPy) (37.0.0) Requirement already satisfied: pyasn1 in /databricks/python3/lib/python3.8/site-packages (from PGPy) (0.4.8) Requirement already satisfied: cffi>=1.12 in /databricks/python3/lib/python3.8/site-packages (from cryptography>=2.6->PGPy) (1.14.5) Requirement already satisfied: pycparser in /databricks/python3/lib/python3.8/site-packages (from cffi>=1.12->cryptography>=2.6->PGPy) (2.20) Python interpreter will be restarted.

@swadeesh - I already applied the workaround by downgrading the crypto library, I have raised this issue because at some point we would need to upgrade the cryptography version