Virtual private networks ( VPNs) can help protect your internet traffic from prying eyes. VPN services route your email, web browsing, and other internet activity through the service provider's servers, making it appear to outsiders that you're only accessing those servers. VPN services help users in China, for example, reach blocked sites by making it appear they’re accessing something else. They also prevent your internet service provider from snooping on the pages you visit, and encrypt web connections that might otherwise be exposed, a handy feature on public Wi-Fi networks.

But VPNs typically come with some major trade-offs. One of the biggest is speed. After all, your traffic must pass through someone else's server before reaching other websites. That extra step inevitably introduces lag. Security company Cloudflare claims its new mobile-only VPN service will be as fast, if not faster, than a traditional mobile connection.

"We wanted to build a VPN service that my dad would install on his phone," says Cloudflare CEO Matthew Prince. "If you tell him that it will make his connection more private and secure, he'd never do it. But if you tell him it will make his connection faster, make his phone's battery last longer, and make his connections more private, then it would be something he'd install."

Mobile phone users can begin signing up for the service, dubbed Warp, through Cloudflare's mobile app 1.1.1.1 on Monday; Cloudflare says it hopes the service is working Monday, but it might take a few days. Regardless, Warp is a sign of things to come for the rest of the internet. The technology that Cloudflare is betting will make Warp fast is a protocol invented by Google called QUIC, and it could one day make the rest of the internet faster and more reliable.

QUIC is essentially a substitute for TCP, the venerable protocol now used for most internet connections. TCP, introduced in 1981, made reliable internet connections possible, says Jana Iyengar, who worked on QUIC for Google; Iyengar is now a distinguished engineer at the cloud computing company Fastly working to help finalize QUIC with the Internet Engineering Task Force standards body.

When you download a page or a file, it might seem like a one-way connection from the server to your phone. Thanks to TCP, your phone and the server are actually engaged in a dialog, as your phone constantly checks in with the server to ensure that it's received all the data the server sent and that the data arrived in the right order. That reliability comes at a cost. The back-and-forth chatter can result in laggy connections. It also has a tendency to sap battery life.

QUIC is built on another protocol called UDP, which is also supported by most existing internet infrastructure. Unlike TCP, UDP doesn't offer much in the way of reliability by default. That's OK for things that don't require strict reliability, like streaming video; but if you're trying to download a file and need to ensure that it isn't corrupted, UDP isn’t much help. But Iyengar says UDP was designed to be expanded. So Google used it to create QUIC, which offers more reliability than vanilla UDP, but with less chattiness than TCP. It also adds baked-in support for encrypted connections.

According to Google's internal testing, QUIC led to 30 percent less "rebuffering" for YouTube users---meaning videos stalled less often---and one second faster loads of Google search pages over slow connections. That might not sound like much, but other Google research found that even a delay of one-fifth of a second can prompt web users to leave a site.