Abstract:This paper proposes a multiple-recipient public key encryption, called pairing-based multi-recipient encryption (PBMRE). The proposed scheme is constructed on Weil pairing on elliptic curves and the Shamir's secrets sharing scheme. As a result, a private key for decryption can be converted to multiple users' private keys by secrets sharing, and reconstructed by the bilinear property of Weil Pairing in decryptions. Through an analysis, it is shown that this scheme is efficient and can effectively defend against deciphers' collaborating. Based on the Gap-BDH (gap-bilinear Diffie-Hellman) assumption and the random oracle model, a strict security proof is presented stating that the scheme has the indistinguishability under adaptive chosen ciphertext attack,简称 (IND-CCA2).