Dr. James Larus is Professor and Dean of the School of Computer and Communication Sciences at EPFL. Prof. Larus has made contributions to several fields spanning programming languages, compilers, computer architecture, and computer systems. He co-led the Wisconsin Wind Tunnel project, started the Singularity project at Microsoft Research (MSR), created Orleans framework for cloud programming as director of the Extreme Computing Group at MSR. He talks to us about privacy-by-design, the associated challenges across the hardware-software stack, and the implications on the design of digital contact-tracing protocols (DP-3T) during the Covid-19 pandemic.