ALPHA

Wireless multi-hop networks are particularly susceptible to attacks based on flooding and the interception, tampering with, and forging of packets. Thus, reliable communication in such networks quintessentially depends on mechanisms to verify the authenticity of network traffic and the identity of communicating peers. A major challenge to achieve this functionality are the tight resource constraints of such devices as smartphones, mesh- and sensor nodes with regard to CPU, memory, and energy. Since existing approaches suffer from significant drawbacks related to functionality and efficiency, we present in this paper ALPHA, an Adaptive and Lightweight Protocol for Hop-by-hop Authentication. ALPHA establishes a verifiable notion of identity for network traffic, based on computationally cheap hash functions, enabling end-to-end as well as hop-by-hop integrity protection for unicast traffic. Our evaluation shows that ALPHA is a generic security mechanism that makes full traffic authentication and secure middlebox signaling viable in resource-constrainted multi-hop networks.