Access Control

We address composition of access control schemes which include both a model to encode authorizations, and an administrative model to encode the manner in which such authorizations can change. The kind of composition we address is co-existence: two schemes working side-by-side in the same system in protection of the same set of resources with the same principals who seek access. We observe that practice appears to be ahead of research in this regard, and discuss case-studies we have carried out of three real-world compositions. We then articulate takeaways from the case-studies.

Changing a Twitter account’s privacy setting between public and protected changes the visibility of past tweets. By inspecting …

Twitter has a relatively simplistic privacy setting of an account being either public or protected, yet many people are still confused about how the settings work. The project looks at various kinds of privacy leakage on Twitter including birth dates, life events, and general knowledge about how the setting feature works.

As digital content becomes more prevalent in the home, nontechnical users are increasingly interested in sharing that content with …