Abstract : This document introduces four schemes that provide per-packet authentication, integrity, and anti-replay services in the context of the Asynchronous Layered Coding (ALC) and NACK-Oriented Reliable Multicast (NORM) protocols. The first scheme is based on RSA Digital Signatures. The second scheme relies on the Elliptic Curve Digital Signature Algorithm (ECDSA). The third scheme relies on a Group- keyed Message Authentication Code (MAC). Finally, the fourth scheme merges the Digital Signature and group schemes. These schemes have different target use cases, and they do not all provide the same service.