Self-sustaining, efficient and forward-secure cryptographic constructions for Unattended Wireless Sensor Networks

Unattended Wireless Sensor Networks (UWSNs) operating in hostile environments face great security and performance challenges due to the lack of continuous real-time communication with the final data receivers (e.g., mobile data collectors). The lack of real-time communication forces sensors to accumulate sensed data possibly for long time periods, along with the corresponding authentication tags. It also makes UWSNs vulnerable to active adversaries, which can compromise sensors and manipulate the collected data. Hence, it is critical to have forward security property such that even if the adversary can compromise the current keying materials, she cannot forge authentication tags generated before the compromise. Forward secure and aggregate signature schemes are developed to address these issues. Unfortunately, existing schemes either impose substantial overhead, or do not allow public verifiability, thereby impractical for resource-constrained UWSNs. In this paper, we propose a new class of cryptographic schemes, referred to as Hash-Based Sequential Aggregate and Forward Secure Signature (HaSAFSS), which allows a signer to sequentially generate a compact, fixed-size, and publicly verifiable signature efficiently. We develop three HaSAFSS schemes, Symmetric HaSAFSS (Sym-HaSAFSS), Elliptic Curve Cryptography (ECC) based HaSAFSS (ECC-HaSAFSS) and self-SUstaining HaSAFSS (SU-HaSAFSS). These schemes integrate the efficiency of MAC-based aggregate signatures and the public verifiability of Public Key Cryptography (PKC)-based signatures by preserving forward security via Timed-Release Encryption (TRE). We demonstrate that our schemes are secure and also significantly more efficient than previous approaches. 2012 Elsevier B.V. All rights reserved.