Biblio

With the development of cloud computing technology, cloud services have been used by more and more traditional applications and products because of their unique advantages such as virtualization, high scalability and universality. In the cloud computing environment, computer networks often encounter security problems such as external attacks, hidden dangers in the network and hidden dangers in information sharing. The network security level protection system is the basic system of national network security work, which is the fundamental guarantee for promoting the healthy development of informatization and safeguarding national security, social order and public interests. This paper studies cloud computing security from the perspective of level protection, combining with the characteristics of cloud computing security. This scheme is not only an extension of information system level protection, but also a study of cloud computing security, aiming at cloud computing security control from the perspective of level protection.

Cloud computing is a modern computing mode based on network, which is widely participated by the public, and provides virtualized dynamic computing resources in the form of services. Cloud computing builds an effective communication platform with the help of computer internet, so that users can get the same computing resources even if they are in different areas. With its unique technical characteristics and advantages, cloud computing has been deployed to practical applications more and more, and the consequent security problems of cloud computing have become increasingly prominent. In addition to the original cloud computing environment, this paper proposes to build a secure cloud with cloud technology, deploy security agents in the business cloud, connect the business cloud, security cloud and security agents through SDN (software defined network) technology, and dynamically divide the business cloud into logically isolated business areas through security agents. Therefore, security is separated from the specific implementation technology and deployment scheme of business cloud, and an information security protection scheme under cloud computing environment is proposed according to the characteristics of various factors, so as to enhance the security of network information.

While Ethereum smart contracts enabled a wide range of blockchain applications, they are extremely vulnerable to different forms of security attacks. Due to the fact that transactions to smart contracts commonly involve cryptocurrency transfer, any successful attacks can lead to money loss or even financial disorder. In this paper, we focus on the overflow attacks in Ethereum, mainly because they widely rooted in many smart contracts and comparatively easy to exploit. We have developed EasyFlow, an overflow detector at Ethereum Virtual Machine level. The key insight behind EasyFlow is a taint analysis based tracking technique to analyze the propagation of involved taints. Specifically, EasyFlow can not only divide smart contracts into safe contracts, manifested overflows, well-protected overflows and potential overflows, but also automatically generate transactions to trigger potential overflows. In our preliminary evaluation, EasyFlow managed to find potentially vulnerable Ethereum contracts with little runtime overhead. A demo video of EasyFlow is at https://youtu.be/QbUJkQI0L6o.

As a common practice in software development, program obfuscation aims at deterring reverse engineering and malicious attacks on released source or binary code. Owning ample obfuscation techniques, we have relatively little knowledge on how to most effectively use them. The biggest challenge lies in identifying the most useful combination of these techniques. We propose a unified framework to automatically generate and optimize obfuscation based on an obscurity language model and a Monte Carlo Markov Chain (MCMC) based search algorithm. We further instantiate it for JavaScript programs and developed the Closure* tool. Compared to the well-known Google Closure Compiler, Closure* outperforms its default setting by 26%. For programs which have already been well obfuscated, Closure* can still outperform by 22%.