On Constructing Optimal One-Time Signatures

One-time signatures (OTS) offer a viable alternative to public keybased digital signatures. OTS security is based only on the strength of the underlying one-way function and does not depend on the conjectured difficulty of a mathematical problem. OTS methods have been proposed in the past but no solid foundation exists for judging their efficiency or optimality. This paper develops a new methodology for evaluating OTS methods and presents optimal OTS techniques for a single OTS or a tree with many OTSs. These techniques can be used in a see-saw mode to obtain desired tradeoff between various parameters such as the cost of signature generation and its subsequent verification and the cost of traditional signature verification and OTS verification.