Efficient certificateless anonymous multi-receiver encryption scheme for mobile devices

With the popularity of mobile devices, how to enhance the security and privacy in wireless communications has gained comprehensive attention. Many cryptographic schemes have been introduced for practical applications. In the multi-receiver encryption (MRE) scheme, a sender is allowed to generate the same ciphertext for a designed group of receivers. Any receiver can get the plaintext by decrypting the ciphertext; however, the real identity of receiver cannot be known by other receivers. Due to the above advantage, the MRE scheme can be used to protect the receiver’s privacy. Recently, the certificateless anonymous multi-receiver encryption (CLAMRE) scheme using the bilinear paring was introduced to solve the certificate management problem existing in MRE schemes based on the public key infrastructure and the private key escrow problem existing in MRE schemes based on identity-based cryptography. However, previous CLAMRE scheme using the bilinear paring is not suitable for mobile devices because the number of bilinear paring operations and Hash-to-Point (HTP) operations executed by the sender increases linearly as the increase of the receivers’ number. In this paper, an efficient CLAMRE scheme based on elliptic curve cryptography for mobile devices is proposed to improve performance. Because no bilinear paring or HTP operation is involved in the process of encryption, the proposed CLAMRE scheme has much less computation cost than the latest CLAMRE scheme. Security analysis shows the proposed CLAMRE scheme is provably secure in the random oracle model.