Publications

This report presents research on public key, digital signature algorithms for cryptographic authentication in low-powered, low-computation environments. We assessed algorithms for suitability based on their signature size, and computation and storage requirements. We evaluated a variety of general purpose and special purpose computing platforms to address issues such as memory, voltage requirements, and special functionality for low-powered applications. In addition, we examined custom design platforms. We found that a custom design offers the most flexibility and can be optimized for specific algorithms. Furthermore, the entire platform can exist on a single Application Specific Integrated Circuit (ASIC) or can be integrated with commercially available components to produce the desired computing platform.

Data authentication as provided by digital signatures is a well known technique for verifying data sent via untrusted network links. Recent work has extended digital signatures to allow jointly generated signatures using threshold techniques. In addition, new proactive mechanisms have been developed to protect the joint private key over long periods of time and to allow each of the parties involved to verify the actions of the other parties. In this paper, the authors describe an application in which proactive digital signature techniques are a particularly valuable tool. They describe the proactive DSA protocol and discuss the underlying software tools that they found valuable in developing an implementation. Finally, the authors briefly describe the protocol and note difficulties they experienced and continue to experience in implementing this complex cryptographic protocol.