Privacy-enhancing technologies (PETs) have attracted significant attention in response to privacy regulations, driving the development of applications that prioritize user data protection. At the same time, the information and communication technology (ICT) sector faces growing pressure to reduce its environmental footprint, particularly its energy consumption. While numerous studies have assessed the energy consumption of ICT applications, the environmental impact of cryptographic PETs remains largely unexplored.

This talk investigates this question by measuring the energy consumption increase induced by three PETs compared to their non-private equivalents: TLS, Searchable Encryption, and Fully Homomorphic Encryption (FHE). Our results reveal highly variable energy consumption increases, ranging from 2× for TLS to 100,000× for FHE. Following these observations, we will discuss various approaches to design (more) sustainable PETs.