Research On Preventing Data Leakage Technology Of Mobile Terminals And Its Application Based On Transparent Encryption

With the advancement of mobile Internet technology and the rapid spread of mobile terminals, people’s way of life and work has undergone tremendous changes. It has brought us great convenience, and caused some problems at the same time, such as data stored in the mobile terminals is excessive and security issues. Due to the limited storage capacity of the mobile terminals, it is difficult to store too much data files, some methods should be adopted to solve the problem of limited storage capaciry. Cloud storage with its easy to use,inexpensive, independent of time and location constraints, etc, the users save the cost of purchasing the physical storage devices, and don’t require maintenance, greatly reduced the users’ storage burden. Thus, it is a good choice to solve the problem of the mobile terminals limited storage capacity, and dump the data files to the cloud servers. Nevertheless, the existing technique in data security protection is still not enough, data exists the risk of being leaked. Therefore, it is necessary to study the data leakage prevention technology to solve the mobile terminals data leakage problems.In order to prevent mobile terminals data leakage in the dump and application. On the one hand, it is necessary to address the data transmission and storage security. On the other hand, the data security in the process of data retrieval is required. Aiming at the security requirements for the above, and take the Product-Study-Research Prospective Joint Reasearch Project of Science and Technology Department of Jiangsu Provincial(BY2013015-23) as the background, the research and application of key technologies of mobile terminals data leakage prevention based on transparent encryption is provided. The main work is as follows:Firstly, taking into account the limited computing power of mobile terminals, in order to improve SMS4 block cipher encryption and decryption efficiency, the algorithm is studied and improved, and a lightweight SMS4 block cipher is proposed. Then apply it to mobile terminals data encryption and decryption with the idea of transparent encryption, it does not require user to understand the specific encryption and decryption process, enhance the users experience.Secondly, Aiming at the problem of ciphertext security retrieval from cloud servers for mobile terminals, in order to ensure the safety and efficiency of the ciphertext retrieval, a privacy-preserving oriented ciphertext retrieval algorithm is proposed. Taking into account the weak computing capability of the mobile terminals, to reduce the computational overhead, a symmetrical searchable encryption scheme is adopted, and a private cloud index server is introduced for separating the index files and ciphertext files. Furthmore, an index structure based trie tree is optimized to improve the efficiency of retrieval, and support sort retrieval for result. The theoretical analysis and experimental results show that the proposed algorithm achieve the privacy guarantee, and a good performance on the stored space and retrieval time.Thirdly, in order to protect the security of mobile terminals data in the cloud servers,through the use of lightweight SMS4 block cipher algorithm for data encryption and decryption, and the privacy-preserving oriented ciphertext retrieval algorithm is adopted for data retrieval. Combined with the idea of transparent encryption, two-factor authenticationtechnology based on device dynamic features and user identity information. Taking Android mobile terminals, cloud storage server for example, a application of mobile terminals data leakage prevention based on transparent encryption is developed. Once the file left the mobile terminals, which will exist in the form of ciphertext is demonstated. Only come back to the original mobile terminal can be decrypted into plaintext, and support for the ciphertext to retrieve securely, achieved the mobile terminals data leakage prevention.