Recently, the concept of cloud computing is appearing, and the cloud storage service becomes a main issue because of its
convenience and low storage cost. The cloud provides storage space service that cloud subscriber (or can be also called cloud user)
can upload his/her own data and store it on cloud. However, the cloud is untrustful or semi-trustful. The cloud subscriber doesn’t want
the cloud provider to know the information about the data. Therefore, serial researches discuss and propose several schemes to secure
the data storage. In 2012, Liao proposed an IC-LOCK approach for the self-reader, which can let cloud subscribers store their data
on the cloud and download data by themselves. However, this approach will cost more computation time. Therefore, we present an
efficient approach based on RSA signature scheme in this paper. The proposed approach does not only inherits the advantages of Liao’s
approach, but also spends less computation cost.