Security Analysis Of Disk Encryption Software

Disk encryption technology has become an important way for people to protect sensitive information. With the disk encryption softwares are widely applied, the security of them has been more and more concerned by people. True Crypt is a encryption software with the highest usage rate, it encrypt and decrypt the encryption volume automatically with on-the-fly encryption technique. Besides, the security of True Crypt has been detected and verified by official, and it is a recognized secure encryption software.This thesis analyzes the security of True Crypt in order to improve the security of all disk encryption softwares. By studying the operational principle, the certification process, and the encryption algorithms of True Crypt, the thesis points out vulnerabilities of True Crypt and some attacks are conducted in experiments. Then the thesis proposes the corresponding methods of security enhancements and confirms the feasibility and the security of True Crypt. The main research contents are shown as follows:Firstly, the thesis analyzes AES key schedule and the keys' distribution in memory in detail, and verifies the property of high entropy, and then extracts AES keys from memory images.Secondly, the study makes use of AES keys extracted from memory images to decrypt True Crypt encryption volumes, and searches for the crucial structure of True Crypt to implement the decryption of encryption volumes.Thirdly, the thesis proposes three methods to strengthen the security of AES algorithm at the source code level and proves the feasibility of these methods by experiments, and analyzes the security and the efficiency of the improved algorithms.