Browsing by Author "Lu, CF"

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Efficient key-evolving protocol for the GQ signature
(2004-07-01)
Lu, CF
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Shieh, S
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資訊工程學系
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Department of Computer Science
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.
Secure key-evolving for public key cryptosystems based on the discrete logarithm problem
(2004-03-01)
Lu, CF
;
Shieh, SP
;
資訊科學與工程研究所
;
Institute of Computer Science and Engineering
This paper addresses the security and efficiency of key-evolving protocols in public key encryption and signature schemes, where the security assumption is the intractability of the discrete logarithm problem. We identify the key-independence property as the security goal of key-evolving, so that each periodic secret key is independent of each other. The first protocol operates in Z(p)* and is efficient for the secret-key holders the second operates in Z(n)*, and is efficient for the public-key holder. For both protocols, we provide proofs and analysis for correctness, security and efficiency.