What is a Warrant Canary?
Canaries are a type of birds that were used in mines, before technology for detecting methane leakages was discovered. When poisonous gas leaked in coal mines, the canaries made a flight of fear, thereby alerting the miners that something was wrong. The same system is now being used by tech companies to indicate that no part of information has been given out to federal agencies. These Warrant Canaries take the form of messages such as “we have not been contacted by anyone for users’ personal information” and similar messages. As long as these messages exist, you can be sure that the website or the ISP is clear. As soon as the message is removed, you have to deduce that the website or the ISP contacted them for information. Though there is freedom of speech, all of us know how it is implemented. If a website or an ISP is contacted by a federal agent for information about a user and the user is informed, the ISP or the website owner is in trouble. It is not allowed by the federal government to contact and inform users that their information has been shared with the feds. But they cannot stop websites or ISPs from displaying messages mentioned above. These messages can take any form and can be worded anyway but the essence of those messages is that they have not been asked for information about any individual using their service. Absence of such messages after a certain period of displaying them makes one understand that the federal agents have contacted the website owners or ISPs to get information about one or more users.
Why would an ISP show Warrant Canaries
Not all ISPs are interested. But the fight against forced procurement of details about users is not acceptable to many. The fight is on for months and especially after the revelation of PRISM, NSA etc. The ISPs may keep quiet if they want. But those who want to fight the system display the Warrant Canaries. The same applies to the website owners. It is purely a matter of choice and to help users understand what is going on.
How does Warrant Canary work literally
The Warrant Canaries can be displayed on the websites continuously until they are contacted by the feds for user information or they can publish a quarterly report saying they were not contacted by anyone for user information during that quarter. In the same way, ISPs too release monthly statements saying they were not contacted for user information in the last one month. They cannot tell that they were contacted by the feds. You have to deduce it yourself if you see the warrant canary absent in the monthly bill/report. It works the same way as the mine canaries flee. In case of warrant canaries, the warrant canary disappears but does not screech or cry about gas leaking.
Aren’t Warrant Canaries illegal?
So far, no court in the US has declared them illegal. Neither have they been confirmed as legal. It is just on the part of ISP or website owner that are willing to fight free speech whether or not to display the warrant canary. As such, there is no law to prevent companies from issuing warrant canaries. If such a law comes up, or if a court actually bans warrant canaries, it will set an example and will be met with a tough resistance: as tough as the resistance to net neutrality and Internet gag motion was met. I, personally, think there is no immediate fear of Warrant Canaries being banned. The government action will provoke people if it does ban Warrant Canaries.