Cryptology ePrint Archive: Report 2010/357

CCA-Secure PRE Scheme without Public Verifiability

Jun Shao and Peng liu and Jian Weng

Abstract: In a proxy re-encryption (PRE) scheme, a semi-trusted proxy can transform a ciphertext under Alice's public key into another ciphertext that Bob can decrypt. However, the proxy cannot access the plaintext. Due to its transformation property, PRE can be used in many applications, such as encrypted email forwarding. All the existing CCA-secure PRE schemes have a crucial property: the public verifiability of the original ciphertext, i.e., everyone can check the validity of the original ciphertext. In this paper, we propose a novel CCA-secure PRE scheme without public verifiability. This proposal is proven-secure based on the DDH assumption in the standard model. To the best of our knowledge, our proposal is the first CCA-secure unidirectional PRE scheme without pairings in the standard model, which answers an open problem in the PRE field.

Category / Keywords: public-key cryptography / proxy re-encryption

Date: received 20 Jun 2010, last revised 16 Aug 2010, withdrawn 29 Aug 2010

Contact author: chn junshao at gmail com

Available format(s): (-- withdrawn --)

Version: 20100829:164328 (All versions of this report)

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