Broadcast encryption method capable of sending private information

Abstract

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.

Description

technical field [0001] The invention belongs to the technical field of computer network security communication, and in particular relates to a broadcast encryption method capable of sending private information. Background technique [0002] The concept of broadcast encryption was first proposed by Fiat and Naor, and it is a secret communication method for multiple receivers. In a general broadcast encryption system, the broadcaster first selects an authorized user set S who can decrypt broadcast encrypted information, then encrypts the broadcast encrypted symmetric key K to obtain the broadcast ciphertext header Hdr, and finally uses the symmetric key K to encrypt the desired The broadcast message is published using the broadcast channel. Only users in the authorized user set S can use their private keys to decrypt and obtain broadcast messages. If all unauthorized users cannot decrypt the broadcast information even if they collude, the broadcast encryption system has comp...

AI Technical Summary

Problems solved by technology

However, the public key length of this method is 3N+2 group elements (N is the number of broadcast users), and the storage cost is relatively high

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