Paper 2007/052

Forward-Secure Sequential Aggregate Authentication

Di Ma and Gene Tsudik

Abstract

Wireless sensors are employed in a wide range of applications. One common feature of most sensor settings is the need to communicate sensed data to some collection point or sink. This communication can be direct (to a mobile collector) or indirect -- via other sensors towards a remote sink. In either case, a sensor might not be able to communicate to a sink at will. Instead it collects data and waits (for a potentially long time) for a signal to upload accumulated data directly. In a hostile setting, a sensor may be compromised and its post-compromise data can be manipulated. One important issue is Forward Security -- how to ensure that pre-compromise data cannot be manipulated? Since a typical sensor is limited in storage and communication facilities, another issue is how to minimize resource consumption due to accumulated data. It turns out that current techniques are insufficient to address both challenges. To this end, we explore the notion of Forward-Secure Sequential Aggregate (FssAgg) Authentication Schemes. We consider FssAgg authentication schemes in the contexts of both conventional and public key cryptography and construct a FssAgg MAC scheme and a FssAgg signature scheme, each suitable under different assumptions. This work represents the initial investigation of Forward-Secure Aggregation and, although the proposed schemes are not optimal, it opens a new direction for follow-on research.