摘要：Cloud computing usage has increased rapidly in many companies. Cloud computing offers many benefits in terms of low cost and accessibility of data. Ensuring the security of cloud computing plays a major role in the cloud computing, as customers often store important information with cloud storage providers but these providers may be unsafe. Customers are wondering about attacks on the integrity and the availability of their data in the cloud from malicious insiders and outsiders, and from any collateral damage of cloud services. These issues are extremely significant but there is still much room for security research in cloud computing. Dealing with “single cloud” providers is predicted to become less popular with customers due to risks of service availability failure and the possibility of malicious insiders in the single cloud. A movement towards “multi-clouds”, or in other words, “interclouds” or “cloud-of-clouds” has increased recently. The purpose of this paper is to survey recent research related to single and multi-clouds security and to address possible solutions. It is found that the research into the use of multi-cloud providers to maintain security has received less attention from the research community than has the use of single clouds. This work aspires to promote the use of multi-clouds due to its ability to reduce security risks that affect the cloud computing consumer.
