Cloud security involves securing the data, applications, and infrastructure associated with cloud computing. The document outlines some common cloud security issues like data breaches, data loss, account hijacking, insecure APIs, denial of service attacks, and back doors. It also discusses how cloud computing works using various deployment models and service models. Finally, it recommends questions users should ask cloud providers about data storage locations, security practices, inspection access, migration costs, disaster recovery documentation, and privacy policies.