One embodiment described herein provides a system and method for isolating data written by different users on a cloud drive. During operation, the system receives a write request from a first user comprising to-be-written data, the to-be-written data being associated with a writer's identifier for the first user. The system then writes the to-be-written data bound with the writer's identifier into physical media associated with the cloud drive, thereby facilitating user data isolation by preventing a second user having a reader's identifier that is different from the writer's identifier of the first user from gaining access to the written data.