Scaling Mobile Private Contact Discovery to Billions of Users

ePrint Report: Scaling Mobile Private Contact Discovery to Billions of Users

Laura Hetz, Thomas Schneider, Christian Weinert

Mobile contact discovery is a convenience feature of messengers such as WhatsApp or Telegram that helps users to identify which of their existing contacts are registered with the service. Unfortunately, the contact discovery implementation of many popular messengers massively violates the users' privacy as demonstrated by Hagen et al. (NDSS '21, ACM TOPS '23). Unbalanced private set intersection (PSI) protocols are a promising …

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