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304 North Cardinal St.
Dorchester Center, MA 02124
Today we’re announcing Private Access Tokens, a completely invisible, private way to validate that real users are visiting your site. Visitors using operating systems that support these tokens, including the upcoming versions of macOS or iOS, can now prove they’re human without completing a CAPTCHA or giving up personal data. This will eliminate nearly 100% of CAPTCHAs served to these users.
What does this mean for you?
If you’re an Internet user:
If you’re a web or application developer:
If you’re a Cloudflare customer:
Over the past year, Cloudflare has collaborated with Apple, Google, and other industry leaders to extend the Privacy Pass protocol with support for a new cryptographic token. These tokens simplify application security for developers and security teams, and obsolete legacy, third-party SDK based approaches to determining if a human is using a device. They work for browsers, APIs called by browsers, and APIs called within apps. We call these new tokens Private Access Tokens (PATs). This morning, Apple announced that PATs will be incorporated into iOS 16, iPad 16, and macOS 13, and we expect additional vendors to announce support in the near future.
Cloudflare has already incorporated PATs into our Managed Challenge platform, so any customer using this feature will automatically take advantage of this new technology to improve the browsing experience for supported devices.
We recently posted about how we used our Managed Challenge platform to reduce our CAPTCHA use by 91%. But because the CAPTCHA experience is so much worse on mobile, we’ve been separately working on ways we can specifically reduce CAPTCHA use on mobile even further.
So, you either can’t use CAPTCHA to protect an API, or the UX is too terrible to use on your mobile website. What options are left for confirming whether a visitor is real? A common one is to look at client-specific data, commonly known as fingerprinting.
You could ask for device IMEI and security patch versions, look at screen sizes or fonts, check for the presence of APIs that indicate human behavior, like interactive touch screen events and compare those to expected outcomes for the stated client. However, all of this data collection is expensive and, ultimately, not respectful of the end user. As a company that deeply cares about privacy and helping make the Internet better, we want to use as little data as possible without compromising the security of the services we provide.
Another alternative is to use system-level APIs that offer device validation checks. This includes DeviceCheck on Apple platforms and SafetyNet on Android. Application services can use these client APIs with their own services to assert that the clients they’re communicating with are valid devices. However, adopting these APIs requires both application and server changes, and can be just as difficult to maintain as SDKs.
This is the most powerful aspect of PATs. By partnering with third parties like device manufacturers, who already have the data that would help us validate a device, we are able to abstract portions of the validation process, and confirm data without actually collecting, touching, or storing that data ourselves. Rather than interrogating a device directly, we ask the device vendor to do it for us.
In a traditional website setup, using the most common CAPTCHA provider:
When PATs are used, device data is isolated and explicitly NOT exchanged between the involved parties (the manufacturer and Cloudflare)
We don’t actually need or want the underlying data that’s being collected for this process, we just want to verify if a visitor is faking their device or user agent. Private Access Tokens allow us to capture that validation state directly, without needing any of the underlying data. They allow us to be more confident in the authenticity of important signals, without having to look at those signals directly ourselves.
With Private Access Tokens, four parties agree to work in concert with a common framework to generate and exchange anonymous, unforgeable tokens. Without all four parties in the process, PATs won’t work.
In the example above, a visitor opens the Safari browser on their iPhone and tries to visit example.com.
This probably sounds a bit complicated, but the best part is that the website took no action in this process. Asking for a token, validation, token generation, passing, all takes place behind the scenes by third parties that are invisible to both the user and the website. By working together, Apple and Cloudflare have just made this request more secure, reduced the data passed back and forth, and prevented a user from having to see a CAPTCHA. And we’ve done it by both collecting and exchanging less user data than we would have in the past.
To take advantage of PATs, all you have to do is choose Managed Challenge rather than Legacy CAPTCHA as a response option in a Firewall rule. More than 65% of Cloudflare customers are already doing this. Our Managed Challenge platform will automatically ask every request for a token, and when the client is compatible with Private Access Tokens, we’ll receive one. Any of your visitors using an iOS or macOS device will automatically start seeing fewer CAPTCHAs once they’ve upgraded their OS.
This is just step one for us. We are actively working to get other clients and device makers utilizing the PAT framework as well. Any time a new client begins utilizing the PAT framework, traffic coming to your site from that client will automatically start asking for tokens, and your visitors will automatically see fewer CAPTCHAs.
We will be incorporating PATs into other security products very soon. Stay tuned for some announcements in the near future.