Question about ssh-rsa deprecation notice (was: Announce: OpenSSH 8.2 released)

Steffen Nurpmeso steffen at
Tue Feb 25 04:31:00 AEDT 2020

Colin Watson wrote in
<20200223112808.GA22328 at>:
 |On Sat, Feb 22, 2020 at 05:06:29PM -0700, Bob Proulx wrote:
 |> Damien Miller wrote:
 |>> Future deprecation notice
 |No, the deprecation notice is talking about the key signature algorithm,
 |not the key type.  SSH clients and servers agree a key signature
 |algorithm as part of their protocol negotiation.  For RSA keys, all of
 |"ssh-rsa", "rsa-sha2-256", and "rsa-sha2-512" exist, using SHA-1,
 |SHA-256, and SHA-512 respectively as their hash algorithms.
 |Unfortunately, the string "ssh-rsa" is used as both a key type name in
 |authorized_keys and as a key signature algorithm name, which has caused
 |a good deal of confusion with this deprecation notice, but the two
 |aren't actually the same thing.
 |My understanding is (and more knowledgeable people should correct me if
 |I'm wrong) that this deprecation notice affects the following people:

Thank you for the above and the following list.  It does not
affect me really, as i used "HostKeyAlgorithms ssh-rsa" and
IdentityFile for the few hosts that use RSA (even exclusively,
like elder Solaris installations i have access to), but
i obviously did not really understand what the RSA change meant.

|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)

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