Systems and methods are described for enabling users to model security resources and user access keys as resources in a template language. The template can be used to create and update a stack of resources that will provide a network-accessible service. The security resources and access keys can be referred to in the template during both stack creation process and the stack update process. The security resources can include users, groups and policies. Additionally, users can refer to access keys in the template as dynamic parameters without any need to refer to the access keys in plaintext. The system securely stores access keys within the system and allows for templates to refer to them once defined. These key references can then be passed within a template to resources that need them as well as passing them on securely to resources like server instances through the use of the user-data field.