International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Time Capsule Signature: Efficient and Provably Secure Constructions

Bessie C. Hu
Duncan S. Wong
Qiong Huang
Guomin Yang
Xiaotie Deng
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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 eĀ±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.
  title={Time Capsule Signature: Efficient and Provably Secure Constructions},
  booktitle={IACR Eprint archive},
  keywords={public-key cryptography / Time Capsule Signature},
  note={Full version 13627 received 24 Apr 2007},
  author={Bessie C. Hu and Duncan S. Wong and Qiong Huang and Guomin Yang and Xiaotie Deng},