Re: Nits in current drafts

[pgut001%cs.auckland.ac.nz@localhost (Peter Gutmann)]

Ben Harris <bjh21%bjh21.me.uk@localhost> writes:

>Does your proposed amendment allow an ssh-rsa signature to use any scheme
>other than RSASSA-PKCS1-v1_5/SHA-1?

Mu :-).  Currently the only scheme defined for ssh-rsa is RSASSA-PKCS1-
v1_5/SHA-1, so it's "Whatever the spec says for ssh-rsa".  If ssh-rsa is at
some point extended to allow (say) .../SHA-256 as well then it'd be
automatically accomodated.

>Does your proposed amendment apply to any key format other than those defined
>by [SSH-TRANS] (currently ssh-rsa and pgp-sign-rsa)?

Well, because it no longer ties the signature format to the key/cert format,
it allows any key format you want, but with a common (and most importantly
well-defined and universally implemented) signature format ssh-rsa (or dsa).
So instead of:

  Key              Sig

  ssh-rsa          ssh-rsa
  pgp-sign-rsa     pgp-sign-rsa
  x509-sign-rsa    x509-sign-rsa
  spki-sign-rsa    spki-sign-rsa
  wibble-sign-rsa  wibble-sign-rsa

where everything in the "Sig" column except ssh-rsa is
underspecified/ambiguous and therefore more or less impossible to achieve
interoperability on, it'd be:

  Key              Sig

  ssh-rsa          ssh-rsa
  pgp-sign-rsa     ssh-rsa
  x509-sign-rsa    ssh-rsa
  spki-sign-rsa    ssh-rsa
  wibble-sign-rsa  ssh-rsa

with the single universal sig format and any key format you want.

Peter.