Error importing package paramiko, then install pynacl

Platform: Openwrt on ARM
please see the attahed logfile when I installed pynacl error

error.log

root@91WK-RT50:~# python
Python 2.7.17 (default, Nov 12 2019, 04:28:16)
[GCC 7.4.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.

import paramiko
Traceback (most recent call last):
File "", line 1, in
File "/usr/lib/python2.7/site-packages/paramiko/init.py", line 22, in
from paramiko.transport import SecurityOptions, Transport
File "/usr/lib/python2.7/site-packages/paramiko/transport.py", line 90, in
from paramiko.ed25519key import Ed25519Key
File "/usr/lib/python2.7/site-packages/paramiko/ed25519key.py", line 22, in
import nacl.signing
File "/usr/lib/python2.7/site-packages/nacl/signing.py", line 17, in
import nacl.bindings
File "/usr/lib/python2.7/site-packages/nacl/bindings/init.py", line 17, in
from nacl.bindings.crypto_aead import (
File "/usr/lib/python2.7/site-packages/nacl/bindings/crypto_aead.py", line 18, in
from nacl._sodium import ffi, lib
ImportError: Error loading shared library /usr/lib/python2.7/site-packages/nacl/_sodium.so: Exec format error
exit()
root@91WK-RT50:# pip install pynacl --log /root/error.log
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
Collecting pynacl
Using cached PyNaCl-1.3.0.tar.gz (3.4 MB)
Installing build dependencies ... error
ERROR: Command errored out with exit status 1: /usr/bin/python2 /usr/lib/python2.7/site-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-V0dtur/overlay --no-warn-script-location -v --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel 'cffi>=1.4.1; python_implementation != '"'"'PyPy'"'"'' Check the logs for full command output.
root@91WK-RT50:#

Begin with the attached error.log and the import path through paramiko/transport.py, paramiko/ed25519key.py, and nacl/_sodium.so; verify the reported OpenWrt ARM and Python 2.7 environment. Done means the cause of the Exec format error is identified and a reproducible resolution is documented or implemented so import paramiko succeeds.