Encrypted Client Hello

Android 17 Adds Local Network Protection and Strengthens Wi-Fi Privacy Controls

Android 17 introduces Local Network Protection, requiring apps to obtain explicit permission before scanning or connecting to devices on the same Wi-Fi network. The feature limits unauthorized discovery of TVs, cameras, printers, consoles and other local equipment that could previously be used to build detailed user profiles. The update also enables Encrypted Client Hello by default to hide domain names during HTTPS handshakes from network observers. Certificate Transparency is now activated by default to detect fraudulent or mis-issued certificates that could enable interception attacks. Additional safeguards block forced downgrades to insecure 2G networks often exploited by fake base stations for SMS-based fraud. These changes collectively reduce passive tracking and man-in-the-middle risks without disrupting legitimate local network functions such as media casting.

HTTPS Lock Icon Present but List of Visited Sites Remains Visible

Even when HTTPS is active and passwords stay protected, DNS queries and the SNI field in TLS handshakes expose the exact domains a user visits over public Wi-Fi. Classic unencrypted DNS over UDP sends domain names in plaintext, allowing anyone on the same network to observe them with simple packet captures. The SNI extension reveals the target hostname before encryption is negotiated, enabling domain-based filtering without decrypting traffic. DNS over HTTPS moves queries inside encrypted channels but shifts visibility to the chosen resolver instead of the local network. Encrypted Client Hello offers partial protection for SNI yet requires support from both browsers and server infrastructure. The practical takeaway is that metadata about services used, timing, and frequency leaks more readily than credentials in modern public networks.