Types for Location and Data Security in Cloud Environments
This addresses security concerns for cloud service users by providing a method to enforce data policies without relying on middleware or preexisting infrastructure, though it is incremental as it builds on existing type system concepts.
The paper tackles the problem of ensuring data security in cloud environments where some devices may be malicious, by presenting a typed language that enforces access restrictions across devices, with the result that well-typed code prevents data leakage even in the presence of untyped or compromised devices.
Cloud service providers are often trusted to be genuine, the damage caused by being discovered to be attacking their own customers outweighs any benefits such attacks could reap. On the other hand, it is expected that some cloud service users may be actively malicious. In such an open system, each location may run code which has been developed independently of other locations (and which may be secret). In this paper, we present a typed language which ensures that the access restrictions put on data on a particular device will be observed by all other devices running typed code. Untyped, compromised devices can still interact with typed devices without being able to violate the policies, except in the case when a policy directly places trust in untyped locations. Importantly, our type system does not need a middleware layer or all users to register with a preexisting PKI, and it allows for devices to dynamically create new identities. The confidentiality property guaranteed by the language is defined for any kind of intruder: we consider labeled bisimilarity i.e. an attacker cannot distinguish two scenarios that differ by the change of a protected value. This shows our main result that, for a device that runs well typed code and only places trust in other well typed devices, programming errors cannot cause a data leakage.