Encrypted Incremental Backup without Server-Side Software

With the development of science and technology, the capacity of hard disk and quantity of data are getting bigger and bigger. Backup become important mechanism for the user or enterprises who don´t want lose their data. When the amount of data is small, it´s fine to do full backup every time. If the amount of data is huge, it will take a long time to do full backup every time. In this case, most enterprise will use incremental backup for saving time. Incremental backup preserves data by not creating multiple copies, therefore incremental backup is faster than full backup. In order to solve security problem, encryption is necessary when backup data storage in storage server. But there is one problem, most incremental backup cannot be encrypted. So, this paper will show how to do encrypted incremental backup without server-side software requirement. Encrypted incremental backup collect information from every file and stores information into one file called checksum file. That information include filename, checksum, last modified time, file size, delete stamp, and encryption key. When backup start, client will collect filename, checksum, last modified time, and file size. Client gets another checksum file from storage server. By comparing those two checksum files, system will know what files have been changed, and should be transmitted in backup at this time. Before those files transmit to storage server, client will generate random keys to encrypt those files, and store encrypted keys in checksum file. System will use another key to encrypt checksum file, and using admin password to encrypt/decrypt this KEK (key encryption key).