Cryptology ePrint Archive: Report 2007/146

Time Capsule Signature: Efficient and Provably Secure Constructions

Bessie C. Hu and Duncan S. Wong and Qiong Huang and Guomin Yang and Xiaotie Deng

Abstract: Time Capsule Signature, first formalized by Dodis and Yum in Financial Cryptography 2005, is a digital signature scheme which allows a signature to bear a (future) time t so that the signature will only be valid at time t or later, when a trusted third party called time server releases time-dependent information for checking the validity of a time capsule signature. Also, the actual signer of a time capsule signature has the privilege to make the signature valid before time t.

In this paper, we provide a new security model of time capsule signature such that time server is not required to be fully trusted. Moreover, we provide two e±cient constructions in random oracle model and standard model. Our improved security model and proven secure constructions have the potential to build some new E-Commerce applications.

Category / Keywords: public-key cryptography / Time Capsule Signature

Publication Info: Full version

Date: received 24 Apr 2007

Contact author: bessiehu at cs cityu edu hk

Available format(s): PDF | BibTeX Citation

Note: This is the full version of the Paper "Time Capsule Signature: Efficient and Provably Secure Constructions" accepted by EuroPKI 2007.

Version: 20070425:081041 (All versions of this report)

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