This is a generic stereotype for the message flow to denote that there is some form of communication protection applied in this message exchange.

1…n data object

1…n data objects

Restriction: message flow must have at least one input-output data objects pair
Error: at least 1 incoming-outgoing pair of data objects is required

Restriction: message flow must have the same number of input and output data objects
Error: number of incoming-outgoing pair of data objects does not match

Restriction: the list of names of input data objects must match the list of names of output data objects
Error: names of incoming and outgoing data objects must match