Suggestion: Deprecate SSH certificates and move to X.509 certificates

Damien Miller djm at
Fri May 25 13:55:35 AEST 2018

No way, sorry.

The OpenSSH certificate format was significantly motivated by X.509's
syntactic and semantic complexity, and the consequent attack surface in
the sensitive pre-authentication paths of our code. We're very happy to
be able to offer certificate functionality while avoiding the numerous
vulnerabilities that X.509/ASN.1 parsing would have brought.

If you really want X.509 certificates, then I'd recommend Roumen
Petrov's patches: -- he's done a
fine job of maintaing these over an extended period of time.


On Fri, 25 May 2018, Yegor Ievlev wrote:

> I suggest deprecating proprietary SSH certificates and move to X.509
> certificates. The reasons why I suggest this change are: X.509
> certificates are the standard on the web, SSH certificates provide no
> way to revoke compromised certificates, and SSH certificates haven't
> seen significant adoption, It's also a bad idea to roll your own
> crypto, and own certificate format seems like an example of this. I
> request comments on this proposal, and suggest that X.509 certificates
> should be supported even if SSH certificates will be left in, since
> that will solve the problem of authenticating a previously unknown
> server using the same mechanism most of the web is using.
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