Cryptology ePrint Archive: Report 2005/431

Is it possible to have CBE from CL-PKE?

Bo Gyeong Kang and Je Hong Park

Abstract: Recently, Al-Riyami and Paterson proposed a generic conversion from CL-PKE (Certificateless Public Key Encryption) to CBE (Certificate Based Encryption) and claimed that the derived CBE scheme is secure and even more efficient than the original scheme of Gentry. In this paper, we show that their conversion is wrong due to the flaw of the security proof. It leads the new concrete CBE scheme by Al-Riyami and Paterson to be invalidated. In addition, our result supports the impossibility to relate both notions in any directions.

Category / Keywords: public-key cryptography /

Date: received 24 Nov 2005, last revised 3 Feb 2006

Contact author: jhpark at etri re kr

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Version: 20060203:120545 (All versions of this report)

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