MICALG registry?

RFC 1847 provides for a required micalg parameter with a
multipart/signed composite media type. But 1847 lists no
values for that parameter, nor does it refer to any sort
of registry of values for it.

RFC 3335 makes use of the micalg parameter and defines
two initial values, md5 and sha1.  But again there's no
mention of any registry or registration procedure for
micalg values.

The closest thing to a registry that I could find is
http-dig-alg, but that's HTTP-specific.

Is there a micalg registry?