The invention belongs to the technical field of the
computer network secret communication, and specifically relates to a
broadcast encryption method capable of sending private information. The method comprises the following steps: 1, setting a
broadcast encryption system parameter, establishing a user set space, generating a public key and a main private key required by the
broadcast system; 2, generating the private key for each use by a PKG and secretly sending the private key to the user; 3, encrypting the broadcasted information by using a symmetric
encryption algorithm with key as K, and encrypting the communication information of the broadcaster and each user by using the symmetric
encryption algorithm with the key as shown in description, and then
broadcasting the generated
ciphertext; and 4, after the user receives the
ciphertext information, if the user belongs to the authorized user set, recovering the key K and the formula as shown in description by using the self private key and the broadcast
ciphertext header Hdr, and respectively decrypting the corresponding
encryption information to recover the
plaintext information. By using the method disclosed by the invention, the
confidentiality, the collusion
attack resistance and the
chosen plaintext attack security are satisfied at the same time; the method has the advantages of being low in expenditure and capable of sending the private information.