International Association
for Cryptologic Research

We investigate a new class of authenticate codes (A-codes) that support verification

by a group of message recipients in the network coding setting. That is, a sender generates an

A-code over a message such that any intermediate node or recipient can check the authenticity

of the message, typically to detect pollution attacks. We call such an A-code as multi-receiver

homomorphic A-code (MRHA-code). In this paper, we first formally define an MRHA-code.

We then derive some lower bounds on the security parameters and key sizes associated with our

MRHA-codes. Moreover, we give efficient constructions of MRHA-code schemes that can be used

to mitigate pollution attacks on network codes. Unlike prior works on computationally secure

homomorphic signatures and MACs for network coding, our MRHA-codes achieve unconditional

security.