Abstract: The security and privacy issues in SNS were studied and a privacy-preserving scheme PPSNS was proposed. PPSNS utilizes attribute-based encryption, allowing the SNS user to set up an enforcement of fine-grained access control upon the data he owns, thus the potential threats from unauthorized parties or even the SNS provider itself could be avoided. A token system in PPSNS is included to address the challenging issue of efficient attribute revocation. In addition, the users in PPSNS don’t have to manage as much information as they do in other encryption-based solutions, achieving a much lower cost in the client side. Analyses show that PPSNS is secure, and gives a better performance in computing and storage costs compared to most related works.