HOW ADVANCED BROWSING PROTECTION WORKS IN MESSENGER

Summary from the TLDR Dev newsletter

Meta's Advanced Browsing Protection (ABP) in Messenger is designed to identify malicious links within end-to-end encrypted chats while rigorously safeguarding user privacy. The system uses a continually updated watchlist of dangerous websites and uses cryptographic primitives, similar to Private Information Retrieval (PIR), to check links without exposing user queries to the server.