Chosen ciphertext secure broadcast encryption in the standard model

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.