A hierarchical key-insulated signature scheme in the ca trust model

Abstract. In key-insulated cryptography, there are many private keys with different indexes and a single, fixed public key. When the trust model includes multiple Certification Authorities (CAs), it can be used to shorten the verification path and mitigate the damage caused by the compromise of a CA’s private key. Existing work requires that the total number of CAs be fixed and that a trusted keystore store all private keys. This paper presents a hierarchical key-insulated signature scheme, called HKI, which converts existing key-insulated methods to a hierarchical scheme. Our scheme allows the system to repeatedly generate a new private key for a new CA and also provides two important features, namely a shortened verification path and mitigated damage. By basing our approach on a general key-insulated scheme, we have made it possible to take advantage of any future improvements in computation complexity, key length, or robustness in current key-insulated methods.

Department of Computer Science Activity 1998-2004

This report summarizes much of the research and teaching activity of the Department of Computer Science at Dartmouth College between late 1998 and late 2004. The material for this report was collected as part of the final report for NSF Institutional Infrastructure award EIA-9802068, which funded equipment and technical staff during that six-year period. This equipment and staff supported essentially all of the department\u27s research activity during that period