Cryptology ePrint Archive: Report 2004/231

Timed-Release and Key-Insulated Public Key Encryption

Jung Hee Cheon and Nicholas Hopper and Yongdae Kim and Ivan Osipkov

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.

Category / Keywords: timed-release, authenticated encryption, key-insulated encryption

Publication Info: Financial Cryptography 2006 (extended version of)

Date: received 9 Sep 2004, last revised 13 Jul 2006

Contact author: osipkov at cs umn edu

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation

Note: Older working version of the paper is available at

Version: 20060713:213306 (All versions of this report)

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