I generated a public/private key (SSH-2 RSA key, 2048 bits) with PuTTY Key Generator. Using Cygwin 2.9.0(0.318/5/3) on Win 10, I used ssh-copy-id from openssh-7.6p1-1 to copy the public key to a CentOS 7.3.1611 with openssh-server 7.4p1. The CentOS
machine would *not* permit logins with the public key's matching private key. I suspect it is because of PuTTY's public key format:

---- BEGIN SSH2 PUBLIC KEY ----
Comment: "rsa-key-20180731" AAAAB3NzaC1yc2EAAAABJQAAAQEAkpDfVicjGj3lD+G73nU9IvTEZXrS9ckH1RKH i1OfzqGjYF1EX6+8cMUc3pL+y0uKIIU1M+e9yDCrUSlWUIP8KSx0ng7G76yopN8J F0mQFvmV6X8cyEmuZ0NhLXXZ2bJ/mgRgWEb1jF3jj1UMiR7/SO0knGpgO2S8EZxj aFyDRcRzFfjj9KBcFgcTcaRAkamNz1ZUMdupb7Yk2f8tR3s6H1jONWRk3s0Gpfdf yyd+KMLDZwR/ie5wZHl9SRZ5Z8sGOhpERaauJuhC5rz+Go3zq0TuWdkCr6QsRv3w JPn70onI5LfS1dijS3du+SXz7RWifFj0rsOJKk3Z9MrBoDUnZw==
---- END SSH2 PUBLIC KEY ----


When I changed the key in the authorized_keys file to the more standard format ssh-rsa AAAAB3NzaC1yc2EAAAABJQAAAQEAkpDfVicjGj3lD+G73nU9IvTEZXrS9ckH1RKHi1OfzqGjYF1EX6+8cMUc3pL+y0uKIIU1M+e9yDCrUSlWUIP8KSx0ng7G76yopN8JF0mQFvmV6X8cyEmuZ0NhLXXZ2bJ/mgRgWEb1jF3jj1UMiR7/
SO0knGpgO2S8EZxjaFyDRcRzFfjj9KBcFgcTcaRAkamNz1ZUMdupb7Yk2f8tR3s6H1jONWRk3s0Gpfdfyyd+KMLDZwR/ie5wZHl9SRZ5Z8sGOhpERaauJuhC5rz+Go3zq0TuWdkCr6QsRv3wJPn70onI5LfS1dijS3du+SXz7RWifFj0rsOJKk3Z9MrBoDUnZw==

then private key login succeeded.

Is this an issue? Should openssh be accepting PuTTY's key format? Or is PuTTY's key format sufficiently obscure that PuTTY should change... should I open a bug?

Thank you.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)