Private Information Retrieval has various applications for any sensitive lookup of data (e.g. medical or financial data), privately retrieving software updates, improving privacy-guarantees of messaging services or improving the scalability of anonymous communication protocols like TOR. However, for many use-cases both computational PIR (cPIR) [1, 2] and information-theoretic PIR (IT-PIR) [3, 4] are not efficient enough for practical use, especially for large database sizes and/or small database entries. While cPIR makes use of homomorphic encryption (HE) and suffers from high computation on the server-side, IT-PIR has large communication costs for databases with many entries.
The goal of this thesis is to implement the hybrid PIR scheme of  making use of both cPIR and IT-PIR (using RAID-PIR [3, 4] and further optimizations) on mobile devices and analyse the performance improvements compared to using only cPIR or only IT-PIR for different database sizes and network settings (including LTE, WiFi, and WAN).
- Good programming skills in C/C++
- Basic knowledge in Android development
- At least basic knowledge of cryptography
- High motivation + ability to work independently
- Knowledge of the English language, Git, LaTeX, etc. goes without saying
-  Sebastian Angel, Hao Chen, Kim Laine, and Srinath Setty. (opens in new tab). In S&P, 2018. PIR with compressed queries and amortized query processing
-  Craig Gentry and Shai Halevi. (opens in new tab). In TCC, 2019. Compressible FHE with applications to PIR
-  Daniel Demmler, Amir Herzberg, and Thomas Schneider. (opens in new tab). In CCSW, 2014. RAID-PIR: Practical multi-server PIR
-  Daniel Demmler, Marco Holz, and Thomas Schneider. (opens in new tab). In ACNS, 2017. OnionPIR: Effective Protection of Sensitive Metadata in Online Communication Networks
-  Casey Devet and Ian Goldberg. (opens in new tab). In PETS, 2014. The best of both worlds: Combining information-theoretic and computational PIR for communication efficiency