Abstract Attribute-Based Encryption (ABE) is a relatively new encryption technology which is similar to multi-receiver encryption but the privacy of ciphertext receivers is protected by a set of attributes such that no one, even the encryptor, knows the identities of the receivers. Although the identities of those receivers remain unknown, the encryptor can ensure that all of the receivers cannot decrypt the ciphertext except for those who match the restrictions on predefined attribute values associated with the ciphertext. However, maintaining the correctness of users¡¦ attributes will take huge cost because the interactions between all users and the key generation center (KGC) are required to renew all of their private keys whenever a user joins, leaves the group, or updates the value of any of his attributes. Since user joining, leaving, and attribute updating may occur frequently in real situations, membership management will become a quite important issue in an ABE system but no existing scheme can perfectly cope with this problem. In this manuscript, we will present an ABE scheme which aims at the issue on dynamic membership management. Our work keeps high flexibility of the constrains on attributes and makes it possible for the procedures of user joining, leaving, and attribute updating to be dynamic, that is, it is not necessary for those users who do not update their attribute statuses to renew their private keys when some user changes his status. Finally, we also formally prove the security of the proposed scheme.