In case of an incomming SSH connection the journal contains the following entry: Accepted publickey for root from ... port ... ssh2: ECDSA SHA256:... that is not helpful to find the real source. in authorized_keys the entries look like ecdsa-sha2-nistp256 ... user@domain It would be very helpful, when the above log message also contains the "user@domain" part. That would make the log message much more helpful. If not, the output should instead of the SHA256 at least contain the same format as the authorized_keys entry has.
*** This bug has been marked as a duplicate of bug 1674 ***
closing resolved bugs as of 8.6p1 release