Currently chaincode developers have no easy way of retrieving information about the invoker/submitter of a transaction. The stub that is passed to the chaincode Invoke function has GetCreator function that return bytes representing the invoker. The chaincode needs to Unmarshal the bytes, read the cert and extract info from it.
The goal is to provide a chaincode API which allows chaincode to implement access control. We want to make these APIs as independent of MSP type as possible, while still allowing value-add for certain types of MSPs.
For more info, pls see https://docs.google.com/document/d/1GP5tcN0oK9Zewed9h5pLiM2BowWPhtgFUGXEDKjeGGo/edit#