Designing a privacy preserving solution on programmable switches

The use of programmable data planes in network research has led to great innovation in the last decade. With programmable data planes, a network administrator can customise and monitor the lowest-level behaviour of network devices via standard open-specific APIs. This offers great flexibility and control to the people operating the network. Research demonstrates that many applications can be transferred from servers to devices such as switches or network cards, taking advantage of the data plane programmability offered by these devices. Along that line of research on programmable data planes, this work proposes the implementation of a privacy-preserving mechanism in the network data plane, leveraging the flexibility of programmable switches and the expressiveness of the domain-specific programming language P4. We choose Differential Privacy (DP) as the target privacy-preserving technique, hence, orienting our data plane design to DP-based mechanisms. Mainly, we show how to implement and assemble Floating Point (FP) operations on P4 targets to build a differential privacy mechanism working on a vector of input elements. Even though data plane programmability is a very active research area, at present, we are not aware of any other work in the literature that presents the implementation of in-switch differential privacy technique. We believe that our initial effort sheds some important light on the challenges and trade-offs to devise such in-network functionality.