Hello list. Based on the current behavior of openssh tools, which are asking for passphrase even without recognizing the key type from header, I was searching for some specification, format or description of the key types accepted and handled by openssh, but without any success. Nor browsing source code helped. I tried several key types in both old or new formats, with or without passphrase, but if I removed header, openssh asked for the passphrase but was never able to decode the key. I am aware of the file [1] which describes new protocol format, but that one has strict header in specification. What is the reason behind decoding every blob received from a file, even if it does not have the proper header? I guess there are some historical reasons but I would like to get more information about this topic. (Background is discussion in our bug [2] about behavior of RSA1 keys with openssh compiled without RSA1 support, where I got to the dead end of my knowledge and of what I was able to find out myself.) [1] https://anongit.mindrot.org/openssh.git/tree/PROTOCOL.key [2] https://bugzilla.redhat.com/show_bug.cgi?id=1282423 Thank you in advance, -- Jakub Jelen Security Technologies Red Hat