Google Adds Support for DNS-over-HTTP/3 in Android to Keep DNS Queries Private

Google on Tuesday officially announced support for DNS-over-HTTP/3 (DoH3) for Android devices as part of a Google Play system update designed to keep DNS queries private.

To that end, Android smartphones running Android 11 and higher are expected to use DoH3 instead of DNS-over-TLS (DoT), which was incorporated into the mobile operating system with Android 9.0.

DoH3 is also an alternative to DNS-over-HTTPS (DoH), a mechanism for carrying out remote Domain Name System (DNS) resolution through an encrypted connection, effectively preventing third parties from snooping on users' browsing activities.

HTTP/3, the first major upgrade to the hypertext transfer protocol since HTTP/2 was introduced in May 2015, is designed to use a new transport layer protocol called QUIC that's already supported by major browsers such as Google Chrome, Microsoft Edge, Mozilla Firefox, and Apple Safari.

The low-latency protocol, developed by Google in 2012, relies on the User Datagram Protocol (UDP) rather than the Transmission Control Protocol (TCP) to make HTTP traffic more secure and efficient, not to mention reduce the time it takes to establish connections between two endpoints.

"While using HTTPS alone will not reduce the overhead significantly, HTTP/3 uses QUIC, a transport that efficiently multiplexes multiple streams over UDP using a single TLS session with session resumption," Matthew Maurer and Mike Yu from the Android team said in a post.

DoH3 further has the advantage of maintaining stable connections even when mobile devices frequently change networks (e.g., from Wi-Fi to LTE). "With DoT, these events require a full renegotiation of the connection. By contrast, the QUIC transport HTTP/3 is based on can resume a suspended connection in a single RTT," Google noted.

Another improvement to take in is the implementation of the DNS resolver in Rust to reduce the risk of security vulnerabilities and enable memory safe guarantees. It's worth pointing out that Google added Rust support to Android in April 2021.

"With the introduction of Rust, we are able to improve both security and the performance at the same time," Maurer and Yu said. "Likewise, QUIC allows us to improve network performance and privacy simultaneously."

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