Tim McHale

**Problem** There is a need to be able to optionally append implementation-specific data to an `application-message` independent of the current `businessProcessMessage` payload. **Solution** Modifications to `/hcs-sxc-java-proto/src/main/proto/Messages.proto` Add: ``` import "google/protobuf/any.proto"...

The signMessage method's default behaviour should be modified to sign the hash of the unencrypted message (as opposed to signing the encrypted message itself)

Small messages or common messages may result in recognisable hashes and or inference of behaviour. We should consider adding entropy into this process. More detail to follow.