Re: Certificate requests for encryption keys

[Stephen Kent <kent@xxxxxxx>]

Brian,

An EE's assertion about binding any key (encryption or signature) to
itself, in the form of a self-signed cert, says little from a security
perspective.  What we are discussing here is whether an EE with an existing
signature key should use it to issue certs for encryption keys.  Yes, one
can do that, but it adds more complexity to key management.  For some apps,
e.g., S/MIME, one wamnts a long term encryption key, for the purposes I
mentioned in my note to Anne.  If there are other Internet applications
that need shorter duration encryption, but not authentication, keys, then
the PKIX WG needs to hear a good description of them, to warrant
appropriate accommodation in our standards.  Note that in places where PFS
is a goal, one can avoid the need for certs entirely for encryption
purposes, e.g., IKE.

Steve