How can I get the current executive user? I need to authenticate the user

I am a beginner.How can I get the current executive user? I need to authenticate the user.
choice RepoWorkFlow_Update_Status_Confirm : ContractId RepoWorkflow
with
eventCate : Text
ctrlParty : Party
ctrlName :Text
controller ctrlParty
do
let currentParty = getParty ctrlName

      assertMsg "preimage mismatching." $ ctrlParty == currentParty

• Here’s my code, maybe formatted a little wrong

The party calling the choice is crtlParty as specified in the controller ctrlParty clause. What are you trying to assert in addition?