What is a warrant canary?

A warrant canary is a method by which a communications service provider informs users that it has NOT been served with a secret government subpoena.

What is a warrant canary?

A warrant canary is a method by which a communications service provider aims to inform its users that the provider has not been served with a secret government subpoena. If the canary is removed, users can infer that such a subpoena has been served.

How do warrant canaries work?

A service provider publishes a regularly updated statement asserting that it has not received any secret legal orders. If the statement stops being updated or is removed, users can infer that the provider has received such an order but is legally prohibited from disclosing it directly.

In some jurisdictions, companies may be legally compelled to provide user data to government agencies and prohibited from disclosing that they have done so. Warrant canaries provide an indirect way to communicate this information.