Abstract: The security issue of cloud computing has received widely attention in recent years. Due to the sharing, out-sourcing and openness features of cloud computing mode, the end-users don’t gain the complete control over their computing and data. Instead, a malicious system operator can tamper with or steal user’s critical data without user’s awareness. Some researchers tried to protect the privacy and integrity of data in the cloud by extending architecture and reduce the hardware/software stack that cloud security relies on. This paper presents technologies in these researches, including enforcing memory isolation, encryption by secure processor, et al.