[openpgp] Revoking Keys: Adding a superceded-by parameter

["Neal H. Walfield" <[e-mail]>]

Hi,

Section 5.2.3.23 describes the reason-for-revocation subpacket.  One
reason is that the key has been superseded.  Unfortunately, there is
no standard, machine-readable way to indicate what the new key is.

I propose that the description field be augmented to include optional
email style headers.  Further, we specify the following header to
specify the new key:

  Superceded-by: fingerprint

Finally, we add that if this extension is used, the whole message
should be signed by the new key (to show that the user controls both
keys).

This amendment has the advantage that it is completely backwards
compatible with existing implementations.

Thoughts?

Thanks,

Neal