Chosen ciphertext secure broadcast encryption in the standard model

摘要

In Eurocrypt'2005, Waters' identity-based encryption scheme suffers a drawback that the scheme only guarantees chosen plaintext security but chosen ciphertext security, and to give concurrent consideration both the efficiency and intract-ability problem in the broadcast encryption, a new identity-based broadcast encryption of chosen ciphertext secure is proposed. The new scheme was regarded as the extended version of Waters' scheme and is based on the standard model. By adding an additional information in ciphertext, the adaptive selective-ID security and the chosen ciphertext security are gained simultaneously in the scheme. The scheme's security is reduced to the decisional bilinear Diffie-Hellman intractability assumption, so the security level is improved and it is suitable for high security environment.