Cryptology ePrint Archive: Report 2008/023
General Certificateless Encryption and Timed-Release Encryption
Sherman S.M. Chow and Volker Roth and Eleanor G. Rieffel
Abstract: While recent timed-release encryption (TRE) schemes are implicitly supported by a certificateless encryption (CLE) mechanism, the security models of CLE and TRE differ and there is no generic transformation from a CLE to a TRE. This paper gives a generalized model for CLE that fulfills the requirements of TRE. This model is secure against adversaries with adaptive trapdoor extraction capabilities, decryption capabilities for arbitrary public keys, and partial decryption capabilities. It also supports hierarchical identifiers. We propose a concrete scheme under our generalized model and prove it secure without random oracles, yielding the first strongly-secure security-mediated CLE and the first TRE in the standard model. In addition, our technique of partial decryption is different from the previous approach.
Category / Keywords: public-key cryptography / security-mediated certificateless encryption, timed-release encryption, standard model
Publication Info: This is the full version of the paper to appear in Security and Cryptography for Networks, 6th International Conference, SCN 2008, Amalfi, Italy, September 10-12, 2008.
Date: received 16 Jan 2008, last revised 23 Jun 2008
Contact author: schow at cs nyu edu
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Version: 20080623:072506 (All versions of this report)
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