IBM Watson IBM Watson IBM Watson In the framework document <draft-irtf-smug-framework-00.txt>, the Secure Multicast Group (SMuG) has identified three functionalities that deal with security transformations for the multicasted data. These are data encryption, source authentication, and group authentication. This document expands on the issues to be taken into consideration when designing transforms that realize these functionalities. These issues include the order of applying the transforms, their placement in the communication layers, possible aggregation of several functionalities in a single transform, and the relationships with other protocols (such as reliable multicast protocols). Next a specific design is proposed, that attempts to meet the requirements of prominent application in a simple yet flexible way.