Privacy is changing how we build computing systems. Recent regulations (e.g., General Data Protection Regulation) require developers to offer greater privacy protections. However, developers struggle to turn these high-level privacy principles into low-level code implementation. The primary cause of this difficulty is that privacy is a multi-stakeholder issue: developers want to achieve more functionality and productivity; users want more control with lower effort; regulators wish to audit systems with limited resources and do not want to stifle innovation; finally, system deployments need to remain proprietary and efficient.

In this talk, I will present a new type of system primitive - Peekaboo - to illustrate that these Human/System requirements must jointly inform system design up-front instead of being afterthoughts. I will describe (1) applying human/system co-design for data minimization, a foundational privacy principle in modern privacy regulation, and (2) how user and other stakeholder experience is transformed in co-designed systems. I will conclude with plans to create a virtuous cycle ecosystem where building trustworthy systems is rewarded, and developers compete to guarantee greater user protection, not less.