The amount of valuable data pertaining to users, such as digital documents, images, and various other important files, has grown exceedingly and needs to be backed up safely. The two most widely used existing backup solutions are the removable devices and the online storage. Problems can arise in the external device backups, for example it takes a long time to burn and copy data files which can result in frequent data loss. Online storage proved to be a better option, but when a large amount of data is to be stored, these third party services become costly. In this paper, a back-up file system is designed, which allows users to store files on their extra disk space. Black-Box is safe for users to back-up their important and secret data. Traditional redundancy schemes focus on storage capacity and computation. However, the proposed Black-Box approach is supported by redundancy mechanisms which include replication and erasure coding.