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Journal of Information Science and Engineering, Vol. 20 No. 4, pp. 763-769 (July 2004)

Efficient Key-Evolving Protocol for the GQ Signature*

Cheng-Fen Lu and Shiuhpyng Shieh+
Department of Computer Science and Information Engineering
Ta Hwa Institute of Technology
Hsinchu, 307 Taiwan
E-mail: cflu@csie.nctu.edu.tw
+Department of Computer Science and Information Engineering
National Chiao Tung University
Hsinchu, 300 Taiwan
E-mail: ssp@csie.nctu.edu.tw

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 signing 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.

Keywords: cryptography, key management, signature scheme, key-evolving protocol, GQ scheme

Full Text () Retrieve PDF document (200407_10.pdf)

Received October 22, 2002; revised May 24, 2003; accepted June 23, 2003.
Communicated by Ja-Ling Wu.
* This work was done while the author was with National Chiao Tung University.