Looking at which key exchange protocols, HMACs etc. various other SSH implementations out there support, it seems that many of them would be barred from accessi

Looking at which key exchange protocols, HMACs etc. various other SSH implementations out there support, it seems that many of them would be barred from accessing a server hardened like that :/. In fact, it almost seems like the intersection of mutually supported protocols is empty resp. only contains known-to-be-unsafe ones... :(. Which makes me wonder: Is there anywhere a comprehensive comparison with tables that show which SSH clients (and servers) support which algorithms for key exchange, HMAC, etc.? That would help determining whom one is going to shut out by disabling which protocol, and thus help in making an informed decision on that. Of course, to be really useful, such a table would also need to take into account which version of each listed software added support for which protocol -- as it is, the OpenSSH shipped in e.g. Mac OS X 10.8 (5.9p1) does not support curve25519-sha256@libssh.org which the OP recommends... Sources: http://www.libssh2.org/ http://www.libssh2.org/ http://api.libssh.org/stable/ http://api.libssh.org/stable/ https://support.ssh.com/manuals/server-admin/44/Ciphers_and_MACs.html https://support.ssh.com/manuals/server-admin/44/Ciphers_and_... http://www.lysator.liu.se/~nisse/lsh/lsh.html http://www.lysator.liu.se/~nisse/lsh/lsh.html