Biblio
As cloud services enter the Internet market, cloud security issues are gradually exposed. In the era of knowledge economy, the unique potential value of big data is being gradually explored. However, the control of data security is facing many challenges. According to the development status and characteristics of database within the cloud environment, this paper preliminary studies on the database security risks faced by the “three-clouds” of State Grid Corporation of China. Based on the mature standardization of information security, this paper deeply studies the database security requirements of cloud environment, and six-step method for cloud database protection is presented, which plays an important role in promoting development of security work for the cloud database. Four key technologies of cloud database security protection are introduced, including database firewall technology, sensitive data encryption, production data desensitization, and database security audit technology. It is helpful to the technology popularization of the grade protection in the security of the cloud database, and plays a great role in the construction of the security of the state grid.
As the adaptive steganography selects edge and texture area for loading, the theoretical analysis is limited by modeling difficulty. This paper introduces a novel method to study pixel-value difference (PVD) embedding scheme. First, the difference histogram values of cover image are used as parameters, and a variance formula for PVD stego noise is obtained. The accuracy of this formula has been verified through analysis with standard pictures. Second, the stego noise is divided into six kinds of pixel regions, and the regional noise variances are utilized to compare the security between PVD and least significant bit matching (LSBM) steganography. A mathematical conclusion is presented that, with the embedding capacity less than 2.75 bits per pixel, PVD is always not safer than LSBM under the same embedding rate, regardless of region selection. Finally, 10000 image samples are used to observe the validity of mathematical conclusion. For most images and regions, the data are also shown to be consistent with the prior judgment. Meanwhile, the cases of exception are analyzed seriously, and are found to be caused by randomness of pixel selection and abandoned blocks in PVD scheme. In summary, the unity of theory and practice completely indicates the effectiveness of our new method.
Malicious Android applications pose serious threats to mobile security. They threaten the data confidentiality and system integrity on Android devices. Monitoring runtime activities serves as an important technique for analyzing dynamic app behaviors. We design a triggering relation model for dynamically analyzing network traffic on Android devices. Our model enables one to infer the dependency of outbound network requests from the device. We describe a new machine learning approach for discovering the dependency of network requests. These request-level dependence relations are used to detect stealthy malware activities. Malicious requests are identified due to the lack of dependency with legitimate triggers. Our prototype is evaluated on 14GB network traffic data and system logs collected from an Android tablet. Experimental results show that our solution achieves a high accuracy (99.1%) in detecting malicious requests sent from new malicious apps.