International Association
for Cryptologic Research

As anonymous social networks continue to grow in popularity, they raise serious challenges around abuse, misinformation, and harmful behavior. While traditional de-anonymization techniques can address misuse, they often come at the cost of user privacy. Protecting honest users' privacy while keeping malicious ones accountable remains a complex challenge. A promising alternative is conditional deanonymization, where anonymity is lifted only when abuse is collectively reported and verified by an authority.

In this work, we present a new cryptographic framework for conditional de-anonymization that preserves user anonymity unless a threshold number of validated abuse reports is reached. Our design leverages threshold cryptography to ensure that de-anonymization can only be triggered under well-defined, collectively enforced conditions—resisting false reports, misuse, and collusion. We formalize the model and provide a generic construction from standard cryptographic primitives, proving strong security guarantees even in the presence of adversarial authorities or malicious users. To illustrate its viability, we also propose a concrete instantiation based on lattice-based assumptions, making it a compelling candidate for post-quantum settings.