Transport privacy is the protection of data while it moves across a network, so local observers cannot easily read what a device is sending or receiving. On an untrusted network, such as public Wi-Fi or a shared hotspot, this usually means encrypting traffic between the user’s device and a trusted endpoint, like a VPN server or secure web service.
This matters because attackers on the same network may sniff packets, capture login sessions, or infer sensitive activity from unencrypted traffic. Transport privacy reduces that exposure by hiding contents and often by limiting metadata visible to nearby observers. It is a defensive layer, not complete protection: it does not stop phishing, malware, or attacks on the device itself. In practice, transport privacy appears in VPNs, HTTPS, secure messaging, and mobile connectivity tools used to keep traffic unreadable outside the trust boundary.