> I assume using AEADs-only makes the MACs keyword obsolete, is this correct? Correct. You can test this by running SSH with -v/--verbose and observing these l

> I assume using AEADs-only makes the MACs keyword obsolete, is this correct? Correct. You can test this by running SSH with -v/--verbose and observing these log lines: debug1: kex: server->client aes256-gcm@openssh.com <implicit> none debug1: kex: client->server aes256-gcm@openssh.com <implicit> none When using a cipher that does not support AEAD, the 2nd field will include the MAC instead of <implicit> debug1: kex: server->client aes256-ctr hmac-sha2-256-etm@openssh.com none debug1: kex: client->server aes256-ctr hmac-sha2-256-etm@openssh.com none I wasn't sure what the 3rd "none" field is, but after some digging it appears to be the compression algorithm: https://github.com/openssh/openssh-portable/blob/master/kex.c#L818 https://github.com/openssh/openssh-portable/blob/master/kex.... And I confirmed this with ssh -C: debug1: kex: server->client aes256-ctr hmac-sha2-256-etm@openssh.com zlib@openssh.com debug1: kex: client->server aes256-ctr hmac-sha2-256-etm@openssh.com zlib@openssh.com