Efficient key-evolving protocol for the GQ signature

Abstract

Several key-evolving protocols for the Guillou-Quisquater (GQ) signature have been proposed. However, the computational loads are still high, which require the multiplication of several modular exponentiations of at least 1024-bit length. In this paper, we present a low-complexity key-evolving protocol with two additional benefits. First, it ensures the secrecy of other signing keys, even when the si.-ning keys in some periods are compromised. Second, it provides the basic time-stamping service, which is important for legal or notary applications. Related schemes are also compared with our scheme.