Hierarchy, rights and authorization

Hierarchies help make information easier to find and understand. For example, most websites use breadcrumbs to show you where you are. Your computer probably has a bunch of drives and deeply nested folders that contain files. We generally use these hierarchical elements to keep data organized, and to keep a tighter grip on rights management. For example, sharing a specific folder with a team, but a different folder could be private.

Although you are free to use Atomic Data with your own custom authorization system, we have a standardized model that is currently being used by some of the tools that we've built.

Design goals

  • Fast. Authorization can sometimes be costly, but in this model we'll be considering performance.
  • Simple. Easy to understand, easy to implement.
  • Handles most basic use-cases. Should deal with basic read / write access control, calculating the size of a folder, rendering things in a tree.

Atomic Hierarchy Model

  • Every Resource SHOULD have a parent.
  • Any Resource can be a parent of some other Resource, as long as both Resources exists on the same Atomic Server.
  • Inversely, every Resource could have children.
  • Only Drives (Resources with the class Drive) are allowed to be a top-level parent.

Authorization

  • Any Resource might have read and write Atoms. These both contain a list of Agents. These Agents will be granted the rights to edit (using Commits) or read / use the Resources.
  • Rights are additive, which means that the rights add up. If a Resource itself has no write Atom containing your Agent, but it's parent does have one, you will still get the write right.
  • Rights cannot be removed by children or parents - they can only be added.
  • Commits can not be edited. They can be read if the Agent has rights to read the subject of the Commit.

Authentication

See authentication.

Current limitations of the current Authorization model

The specification is growing (and please contribute in the docs repo), but the current specification lacks some features:

  • Rights can only be added, but not removed in a higher item of a hierarchy. This means that you cannot have a secret folder inside a public folder.
  • No model for representing groups of Agents, or other runtime checks for authorization.
  • No way to limit delete access seperately from write rights
  • No way to request a set of rights for a Resource