Stream processing architectures have been proposed as efficient and flexible platforms for network packet processing. As part of an investigation into stream-based network processors, we have implementedMMH, a family of almostuniversal hash functions for message authentication, on a SIMD stream processor (Imagine). The hash computation over an entire packet is a good fit for the stream programming model, with an abundance of producer-consumer locality: hash values are computed and stored in the stream register file (SRF), then used for calculating new hash values repeatedly. By using eight VLIW clusters, the construction is performed in a Multi-SIMDfashion, achieving multi- Gigabit-per-second throughput with a collision probability on the order of 2^-120 .