’Don’t Annoy Me With Privacy Decisions!’ — Designing Privacy-Preserving User Interfaces for SSI Wallets on Smartphones

Persistent digital identities allow individuals to prove who they are across the Internet. For decades, individuals have relied on large identity providers (for example, Google and Facebook). In recent years, the advent of so-called self-sovereign identities (SSI) has increasingly been approved by national governments. This decentralized approach provides users with a way to maintain control over the information associated with their identities. Yet, the design of these wallets to enable users to act in a privacy-preserving manner when sharing data with requesting services remains an open question. Based on a qualitative pre-study, we chart the design space for privacy-preserving user interfaces for SSI wallets and explore several designs to understand user adoption and decision-making processes. A qualitative user study (N=16) based on realistic scenarios revealed that while the proposed designs generally increase privacy awareness, participants trade data for convenience. Our study is complemented by guidelines for designers of future user interfaces for smartphone SSI wallets.