Debugging privacy-preserving protocols is hard. Oblivious HTTP has several different steps across four different parties, not to mention binary HTTP encoding and details spread across many draft RFCs. We've taken what we've learned operating protocols like Oblivious HTTP at the scale of millions of requests per second, and wrapped it up in a nice, clean CLI tool — that we are open-sourcing today.
We call it our privacy-client, or pvcli. We’re releasing it under the Apache-2.0 License, and it is open for contributions.
Here’s a single line of code that executes a full Oblivious HTTP request with a relay, gateway and origin. Don't worry if you don't know what that means, we'll cover it below.
We’ll explain why we built this tool, and show just how handy it can be.
Why privacy protocols can be hard to debug
Let’s take a closer look at our motivation for creating pvcli. Over time, the Privacy team’s product suite and customer base grew. We added products like Privacy Proxy and Privacy Gateway, which power Apple’s Private Relay, Microsoft’s Edge Secure Network VPN, Flo Health’s Anonymous Mode, and more. With it came an increasing amount of special customer requirements, domain knowledge, and complexity. As a result, we saw increased friction in development and incident response.
To see this in action, let’s look at how one of our products implements Oblivious HTTP, also known as OHTTP. First, a quick primer. OHTTP provides users with a privacy guarantee: no one can know both who made a request and what they’re requesting. To achieve this, OHTTP requires two servers, a relay and a gateway, operated by two non-colluding parties.
Below is a sequence diagram of OHTTP, where our customer owns the relay and Cloudflare owns the gateway. At
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Source: Cloudflare Blog (Published: Mon, 27 Jul 2026 13:00:00 GMT). Read the full article on the original site.
