Hashes, names, and normalization

We've got a couple of KeyAlgorithm interfaces that specify hashes by
KeyAlgorithm, namely in HmacKeyIdentifier and RsaHashedKeyAlgorithm.  While
I like recursion as much of the next guy, this seems like it leads to
ambiguity for the web developer, since there's not a canonical form for
specifying hashes in this way.

Could we just replace the KeyAlgorithm with a DOMString that names the
hash?  It seems like that would only become an issue if we had parametrized
hashes that we wanted to use with HMAC/RSA-PKCS1.  I'm not aware of any
such hashes that we have use cases for right now.

(And if we were envisioning { name: "SHA-X" }, that's just excessive.)

In WebIDL terms:

[NoInterfaceObject]
interface RsaHashedKeyAlgorithm : RsaKeyAlgorithm {
  // The name of the hash algorithm that is used with this key
  readonly attribute DOMString hash;
};

[NoInterfaceObject]
interface HmacKeyAlgorithm : KeyAlgorithm {
  // The name of the inner hash function to use.
  readonly attribute DOMString hash;
};

(Oh, and by the way, the [NoInterfaceObject] directive is missing from
HmacKeyAlgorithm in the current ED.)

--Richard