Following trace suggests, that the current version of python-paramiko in Leap
15.4 (i.e. python-paramiko 2.4.2-150100.6.12.1) is suffering from a known bug
https://github.com/paramiko/paramiko/issues/1306

File "/usr/lib/python3.6/site-packages/paramiko/client.py", line 749, in _auth
raise saved_exception
File "/usr/lib/python3.6/site-packages/paramiko/client.py", line 720, in _auth
filename, pkey_class, passphrase
File "/usr/lib/python3.6/site-packages/paramiko/client.py", line 571, in
_key_from_filepath
key = klass.from_private_key_file(key_path, password)
File "/usr/lib/python3.6/site-packages/paramiko/pkey.py", line 217, in
from_private_key_file
key = cls(filename=filename, password=password)
File "/usr/lib/python3.6/site-packages/paramiko/ed25519key.py", line 81, in
__init__
signing_key = self._parse_signing_key_data(data, password)
File "/usr/lib/python3.6/site-packages/paramiko/ed25519key.py", line 156, in
_parse_signing_key_data
message = Message(unpad(private_data))
File "/usr/lib/python3.6/site-packages/paramiko/ed25519key.py", line 41, in
unpad
raise SSHException("Invalid key")
paramiko.ssh_exception.SSHException: Invalid key


According to changelog, the solution would be to upgrade to version at least
2.5.1 (we currently have 2.11 in TW). As an alternative, the fix
(https://patch-diff.githubusercontent.com/raw/ploxiln/paramiko-ng/pull/5.patch)
seems to be also back-ported into 2.4 branch as version 2.4.3.