Warrant canary
From Wikipedia, the free encyclopedia
A warrant canary is a method used by a web hosting service to inform their customers that the provider has not been served with a secret government subpoena. Such warrants, including those covered under the USA Patriot Act, provide for criminal penalties for revealing the warrant to customers. A warrant canary may be posted by the provider to inform customers of dates that they haven't been served a secret warrant. If the canary has not been updated in the time period specified by the host, customers are to assume that they have been provided with a warrant. Theoretically, this allows the provider to inform customers of subpoenas without violating any laws. The legality of this has not been tested in any court, however.
A warrant canary may include a digital signature as proof that the message was written by the hosting provider.
Warrant canaries were first used by rsync.net. In addition to a digital signature, they provide a recent news headline as proof that the warrant canary was recently posted.[1]
