CCA-secure Identity Based Proxy Re-encryption Based on a Variant of BB1 IBE

In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice's public key into one that can be opened under Bob's decryption key. In this paper, with the help of the PKG, we construct a CCA-secure identity based proxy reencryption scheme based on a variant of BBi identity based encryption (IBE), we also prove its security in the random oracle model.