Science gateways have emerged as a concept for allowing large numbers of users in communities to easily access high-performance computing resources which previously required a steep learning curve to utilize. In order to reduce the complexity of managing access for these communities, which can often be large and dynamic, the concept of community accounts is being considered. This paper proposes a security model for community accounts, organized by the four As of security: Authentication, Authorization, Auditing and Accounting.A AAAA MODEL ‡ We could envision larger communities taking a lead role, but we believe that resource owners will continue to take the lead most often and so concentrate on that scenario.