Chosen-Ciphertext Secure Proxy Re-Encryption without Pairing

• Main Authors: DENG, Robert H., Weng, Jian, LIU, Shengli, CHEN, Kefei
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 2008
• Subjects: Proxy re-encryption; bilinear pairing; chosen-ciphertext security; Information Security
• Online Access: https://ink.library.smu.edu.sg/sis_research/295; https://ink.library.smu.edu.sg/context/sis_research/article/1294/viewcontent/2008_509.pdf
• Institution: Singapore Management University

In a proxy re-encryption system, a semi-trusted proxy can convert a ciphertext originally intended for Alice into a ciphertext intended for Bob, without learning the underlying plaintext. Proxy re-encryption has found many practical applications, such as encrypted email forwarding, secure distributed file systems, and outsourced filtering of encrypted spam. In ACM CCS'07, Canetti and Hohenberger presented a proxy re-encryption scheme with chosen-ciphertext security, and left an important open problem to construct a chosen-ciphertext secure proxy re-encryption scheme without pairings. In this paper, we solve this open problem by proposing a new proxy re-encryption scheme without resort to bilinear pairings. Based on the computational Diffie-Hellman (CDH) problem, the chosen-ciphertext security of the proposed scheme is proved in the random oracle model.