| Nowadays,social networks store a lot of personal data. Due to the protection measures on the users’ secret data are inadequate, the personal data is leaked. Social networks can provide the information sharing, and it is an interesting challenge to provide the protection for the privacy data under the condition of information sharing. As a new cryptographic primitive, attribute-based cryptography is an attractive research in recent years. It can provide a fine-grained access control mechanism of encrypted data. Hence, attribute-based cryptography provides a new proposal for the protection of privacy in the social network.Based on the characteristics of the social network and the technology of the attribute-based encryption, a fined-grained access control scheme by using the attribute-based encryption algorithm is proposed to solve the problem of privacy protection in social network. The proposed scheme utilizes a linear secret sharing scheme to construct the access policies in order to achieve flexible access structure. It can transfer most of computing overwork involved in re-encryption to social network platform, which greatly reduces the computational cost of users while keeps the data security. The social network platform analyzes the relationship between the unauthorized users and authorized users to determine the access rights of unauthorized users. The proposed scheme can achieve the transitivity of the access rights. The results show that the new scheme has higher performance and security.Ciphertext policy attribute-based encryption mechanisms mostly use a single authority to manage and distribute users’ keys, which can easily lead to system bottlenecks. To solve this problem, we propose a multi-authority ciphertext policy attribute-based encryption access control scheme for social network. In this scheme, we realize the splitting and reconstruction of secrets by using the linear secret sharing technique and the attribute revocation by using the re-encryption technique. The scheme outsources some decryption computation tasks to the social network platform in decryption process, which can reduce the computational cost of users. The results show that the proposed scheme can reduce the computational cost of a single authority and can resist the collusion attack. |
