This document discusses technical security issues in cloud computing. It begins with an introduction to cloud computing and outlines some of the main security concerns when relying on external companies to store and process data in the cloud. These concerns include data confidentiality, safety and privacy. The document then surveys related work on web service and transport layer security. It proceeds to examine specific security issues in cloud computing like XML signature issues, browser security vulnerabilities, risks of cloud integrity and binding failures, and flooding attacks. It concludes by noting that improving cloud security requires strengthening the security of both web browsers and web service frameworks.