A canary notice or a warrant canary is a notice through which a company is able to state that it has not so far received a secretive government request for user data. Warrant canaries are named after canaries which used to be sent down mine-shafts in order to see whether there were any toxic gases present, with the death of the canary alerting workers about danger lying ahead. In the same manner, the non-existence of the canary notice on a website can alert its users to the fact that they may have received the secret requests.
- A National Security Letter is an example of a secret government request for user data in the United States.
Reddit is a prominent example of a website known to have taken down its warrant canary.
Warrant canaries are illegal in Australia.
Lavaboom was a secure email service which closed after its warrant canary was taken down.
Last updated: 5 November 2017