Cryptography, applied

Texting and social media-based messaging applications have become nearly as common as face-to-face communications for conversation between individuals and groups. While it is known how to provide privacy for conversations between two individuals, there is a gap in extending these techniques to group conversations. This project is developing new communication techniques and open-source software for private communication among groups of users.

This project addresses how semiconductor designers can verify the correctness of ICs that they source from possibly untrusted fabricators. Existing solutions to this problem are either based on legal and contractual obligations, or use post-fabrication IC testing, both of which are unsatisfactory or unsound. As a sound alternative, this project designs and fabricates verifiable hardware: ICs that provide proofs of their correctness for every input-output computation they perform in the field.

Common smartphone authentication mechanisms such as PINs, graphical passwords, and fingerprint scans offer limited security. They are relatively easy to guess or spoof, and are ineffective when the smartphone is captured after the user has logged in. Multi-modal active authentication addresses these challenges by frequently and unobtrusively authenticating the user via behavioral biometric signals, such as touchscreen interaction, hand movements, gait, voice, and phone location.

Open-audit cryptographic voting protocols enable the verification of election outcomes, independent of whether election officials or polling machines behave honestly. Many open-audit voting systems have been prototyped and deployed. The City of Takoma Park, MD held its 2009 and 2011 city elections using voting system Scantegrity. Systems with similar properties are being proposed for use in Victoria, Australia (the Pret a Voter system) and Travis County, Texas (the STAR-Vote system).

The primary goal of this project is to develop a mathematical foundation underlying the analysis of modern cryptosystems. Cryptography is a core tool used to secure communications over the Internet. Secure and trustworthy communications and data storage are essential to national security and to the functioning of the world economy. Recent spectacular research results have enabled the development of new types of cryptography, exciting new potential applications, and hopes for stronger guarantees of cryptographic security in the long term.