What additions/extension to CashID is needed for it to be used in this way? Is the "sign" action (a=sign&d=data) sufficient?
I'm thinking that custom memosign actoin is better UX.
I'm not sure yet, but probably a custom action like you said. Delegated keys is something I was hoping to start working on in next few months. Once I dig in I'll know more.
While for a custom action, the identity manager / wallet could both sign, build and broadcast the TX, then return TXID in response.
For compatibility, offer a generic solution as well
Based on MIP, there is two actions sign: one that grant, and one that revoke, permission.
Generic a=sign&d=data can be used, but memo client would need to build and broadcast TX.
