The Transparent Encryption System Based On File Filter Driver Design And Implementation

With several decades of developing after the coming out of computer, ComputerScience and Information Technology have made tremendous progress, especially afterthe emergence of Internet in1990s. The progress has brought great convenience topeople’s lives and production. Nowadays, more and more information is stored incomputer system, which is also shared and managed via Internet, this informationoperating approach has made a tremendous social economic benefit.However, in the process of social informatization promoted by ComputerTechnology and Information Technology, information security problem is becomingincreasingly prominent. For instance, the broad spreading of computer viruses andTrojans, the illegal invasion of hackers and information leak of digital confidentialdocuments are happened frequently and endlessly, which made a huge economic lossesand bad influence in society.Under this circumstance, a lot of protection technology and products are researchedand realized in Information Security domain to solve those security problems mentionedabove. These technology and products included Anti-virus software, Trojan protectionsoftware, Network Firewall, Intrusion Detection System, Access Management Systemand File Encryption System, and so on. These technology and products solved thesecurity problems in the process of informatization very well.This thesis researches the file transparent encryption technology used forprotecting the information saved in digital files, including the introduction ofdeveloping process, research status, developing tide, and the deeply research of FileFilter Driver used in file transparent encryption. Based on the work mentioned above,this thesis designed and realized a file transparent encryption system MiniEncryptorbased on minifilter provided by Microsoft.MiniEncryptor is running on the Windows OS based on NT kernel, and loadinginto the OS as a kernel module, with the ability of filtering all the file IO operations.After the file IO operations are filtered, MiniEncryptor analyzes the file IO operationsaccording to the encryption rules set by the users, and provides the service of encryption and decryption automatically if the file IO operation needs encryption or decryption.The process of encryption and decryption is transparent to users. And beyond that,MiniEncryptor also provides a management UI program, which can be use by users toload configuration information and obtain file operation information.MiniEncryptor is running in the kernel mode in Windows OS, so it has a highencryption efficiency, strong self-security and good ease of use.