International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Timed-Release and Key-Insulated Public Key Encryption

Jung Hee Cheon
Nicholas Hopper
Yongdae Kim
Ivan Osipkov
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Abstract: In this paper we consider two security notions related to Identity Based Encryption: Key-insulated public key encryption, introduced by Dodis, Katz, Xu and Yung; and Timed-Release Public Key cryptography, introduced independently by May and Rivest, Shamir and Wagner. We first formalize the notion of secure timed-release public key encryption, and show that, despite several differences in its formulation, it is equivalent to strongly key-insulated public key encryption (with optimal threshold and random access key updates). Next, we introduce the concept of an authenticated timed-release cryptosystem, briefly consider generic constructions, and then give a construction based on a single primitive which is efficient and provably secure.
  title={Timed-Release and Key-Insulated Public Key Encryption},
  booktitle={IACR Eprint archive},
  keywords={timed-release, authenticated encryption, key-insulated encryption},
  note={Financial Cryptography 2006 (extended version of) 13342 received 9 Sep 2004, last revised 13 Jul 2006},
  author={Jung Hee Cheon and Nicholas Hopper and Yongdae Kim and Ivan Osipkov},