Assure Information Flows

Freedom and openness of the Internet are under threat. Government censors in non-democratic countries are deploying network filters to block sources of uncensored information, suppress dissent, and prevent citizens from using the Internet to exercise their human rights such as freedom of speech and freedom of assembly.

The modern web experience is dynamic, providing users with a highly responsive interface through which to interact with the world. Today's mechanisms allow servers---even those which are controlled by an attacker---to download arbitrary programs into a user's browser. It is extraordinarily difficult to secure the web browser (and its user) against attack in this scenario. While tools and techniques are useful to analyze and restrict downloaded code, they are by their very nature incomplete. As a result, the security of web services relies on a series of ad hoc, service-provided techniques.

As companies collect consumer data in increasingly larger quantity and mine the data more deeply, trade-offs arise with respect to companies' practices about information privacy. A company may choose practices that augment targeted advertisements or services. However, the financial rewards associated with privacy practices are highly uncertain, since they are affected by a company's competition with rivals.

Access control refers to mechanisms for protecting access to confidential information, such as sensitive medical data. Management of access control policies, in applications that involve several collaborating parties, poses several challenges. One of these is in ensuring that each party in such a collaboration only obtains the minimal set of access permissions that they require for the collaboration. In a domain such as healthcare, it may be critical that access be minimized in this way, rather than allowing all parties equal access to the sensitive information.

Blockciphers are the basic building block of shared-key cryptography. However, for certain important cryptographic goals, like building encryption schemes, the interface presented by blockciphers is limiting. A more modern primitive, the tweakable blockcipher (TBC), is often a better fit. Like a blockcipher, a TBC takes as input a secret key, a block of data and the tweak which is an additional input which provides variability to the TBC's input-output behavior without having to change the secret key.