Relaxing tamper-resistance requirements for smart cards by using (auto-)proxy signatures

摘要

We address the problem of relaxing tamper-resistance requirements for smart cards by deriving short-term asymmetric keys from a long-term asymmetric signature key, while increasing as few as possible the amount of memory necessary to store them. This leads us to consider (auto-)proxy signatures in the sense of Mambo, Usada and Okamoto [MUO], and to provide a generic and secure method for constructing such schemes. Then we give six different schemes generated this way, among which all the proxy signature schemes known to date appear as particular cases, and compare them in terms of efficiency, flexibility and transparency.