Public-Key-Pins-Report-Only

Deprecated
This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Note: Public Key Pinning mechanism was deprecated in favor of Certificate Transparency and Expect-CT header.

The HTTP Public-Key-Pins-Report-Only response header sends reports of pinning violation to the report-uri specified in the header but, unlike Public-Key-Pins still allows browsers to connect to the server if the pinning is violated.

For more information, see the Public-Key-Pins header reference page and the HTTP Public Key Pinning article.

Header type Response header
Forbidden header name no

Syntax

Public-Key-Pins-Report-Only: pin-sha256="<pin-value>"; 
                             max-age=<expire-time>; 
                             includeSubDomains; 
                             report-uri="<uri>"

Directives

pin-sha256="<pin-value>"
The quoted string is the Base64 encoded Subject Public Key Information (SPKI) fingerprint. It is possible to specify multiple pins for different public keys. Some browsers might allow other hashing algorithms than SHA-256 in the future.
max-age=<expire-time>
This directive is meaningless for the Public-Key-Pins-Report-Only header, it will be ignored by user agents and the header will not be cached.
includeSubDomains Optional
If this optional parameter is specified, this rule applies to all of the site's subdomains as well.
report-uri="<uri>"
Pin validation failures are reported to the given URL. This directive should be used with this header, otherwise this header will be a no-op.

Example

Public-Key-Pins-Report-Only: 
  pin-sha256="cUPcTAZWKaASuYWhhneDttWpY3oBAkE3h2+soZS7sWs="; 
  pin-sha256="M8HztCzM3elUxkcjR2S5P4hhyBNf6lHkmjAHKhpGPWE="; 
  includeSubDomains; 
  report-uri="https://www.example.org/hpkp-report"

In this example, pin-sha256="cUPcTAZWKaASuYWhhneDttWpY3oBAkE3h2+soZS7sWs=" pins the server's public key used in production. The second pin declaration pin-sha256="M8HztCzM3elUxkcjR2S5P4hhyBNf6lHkmjAHKhpGPWE=" also pins the backup key. This key pinning is also valid for all subdomains, which is told by the includeSubDomains declaration. Finally, report-uri="https://www.example.org/hpkp-report" explains where to report pin validation failures.

Specifications

Specification Title
RFC 7469, section 2.1: Public-Key-Pins-Report-Only Public Key Pinning Extension for HTTP

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Public-Key-Pins-Report-Only
Deprecated
Chrome No support 46 — 72Edge No support NoFirefox No support No
Notes
No support No
Notes
Notes See bug 1091177.
IE No support NoOpera No support 33 — 60Safari No support NoWebView Android No support NoChrome Android No support ? — 72Firefox Android No support NoOpera Android No support 33 — 51Safari iOS No support NoSamsung Internet Android No support 5.0 — 11.0

Legend

No support  
No support
Deprecated. Not for use in new websites.
Deprecated. Not for use in new websites.
See implementation notes.
See implementation notes.

See also