Normative Ballot.

I suggest that Bundle.signature (and Provenance.signature) are removed and added to Meta – so they would become Bundle.meta.signature and Provenance.meta.signature, respectively.

This would allow for the signing of any resource type in the future, and puts metadata where it belongs (in meta).

I would also suggest adding a new common search parameter called _signature which would target Resource.meta.signature.who[x] and Resource.meta.signature.onBehalfOf[x].