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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.
Contents
- Usage
- Companies and organizations with warrant canaries
- Companies and organizations who no longer have warrant canaries
- Canary Watch
- References
Secret subpoenas, such as those covered under 18 U.S.C. §2709(c) of the USA Patriot Act, provide criminal penalties for disclosing the existence of the warrant to any third party, including the service provider's users. A warrant canary may be posted by the provider to inform users of dates that they have not been served a secret subpoena. If the canary is not updated for the time period specified by the host or if the warning is removed, users are to assume that the host has been served with such a subpoena. The intention is to allow the provider to warn users of the existence of a subpoena passively, without disclosing to others that the government has sought or obtained access to information or records under a secret subpoena.
United States secret subpoenas or national security letters originated in the 1986 Electronic Communications Privacy Act to be used only against those suspected of being agents of a foreign power. This was revised in 2001 under the Patriot Act so that secret subpoenas can be used against anyone who may have information deemed relevant to counter-intelligence or terrorism investigations. The idea of using negative pronouncements to thwart the nondisclosure requirements of court orders and served secret warrants was first proposed by Steven Schear on the cypherpunks mailing list, mainly to uncover targeted individuals at ISPs. It was also suggested for and used by public libraries in 2002 in response to the USA Patriot Act, which would force librarians to disclose the circulation history of any of their patrons.
Usage
The first commercial use of a warrant canary was by the US cloud storage provider rsync.net, which began publishing its canary in 2006. In addition to a digital signature, it provides a recent news headline as proof that the warrant canary was recently posted as well as mirroring the posting internationally.
On November 5, 2013, Apple became the most prominent company to publicly state that it had never received an order for user data under Section 215 of the Patriot Act. On September 18, 2014, GigaOm reported that the warrant canary statement did not appear anymore in the next two Apple Transparency Reports, covering July–December 2013 and January–June 2014. Tumblr also included a warrant canary in the transparency report that it issued on February 3, 2014. In August 2014, the online cloud service Spider Oak implemented an encrypted warrant canary that publishes an "All Clear!" message every 6 months. Three PGP signatures from geographically distributed signers must sign each message — so if a government agency forced SpiderOak to update the page, they would need to enlist the help of all three signers.
In September 2014, US security researcher Moxie Marlinspike wrote that "every lawyer I've spoken to has indicated that having a 'canary' you remove or choose not to update would likely have the same legal consequences as simply posting something that explicitly says you've received something."
Australia outlawed the use of a certain kind of warrant canary in March 2015, making it illegal for a journalist to "disclose information about the existence or non-existence" of a warrant issued under new mandatory data retention laws. It is unlikely a journalist could give a correct canary in this situation anyway, as under this legislation the agency obtaining the warrant is not compelled to inform the journalist of the warrant. Afterwards, computer security and privacy specialist Bruce Schneier wrote in a blog post that "[p]ersonally, I have never believed [warrant canaries] would work. It relies on the fact that a prohibition against speaking doesn't prevent someone from not speaking. But courts generally aren't impressed by this sort of thing, and I can easily imagine a secret warrant that includes a prohibition against triggering the warrant canary. And for all I know, there are right now secret legal proceedings on this very issue."
Companies and organizations with warrant canaries
The following is a list of companies and organizations with warrant canaries:
Companies and organizations who no longer have warrant canaries
The following is a list of companies and organizations whose warrant canaries no longer appear in transparency reports:
Canary Watch
In 2015, a coalition of organizations consisting of the EFF, Freedom of the Press Foundation, NYU Law, the Calyx Institute, and the Berkman Center created a website called Canary Watch in order to provide a compiled list of all companies providing warrant canaries. Its mission was to provide prompt updates of any changes in a canary's state. It is often difficult for users to ascertain a canary's validity on their own and thus Canary Watch aimed to provide a simple display of all active canaries and any blocks of time that they were not active. In May 2016, it was announced that Canary Watch "will no longer accept submissions of new canaries or monitor the existing canaries for changes or take downs". The coalition of organizations which created Canary Watch explained their decision to discontinue the project by stating that it has achieved its goals to raise awareness about "illegal and unconstitutional national security process, including National Security Letters and other secret court processes." The Electronic Frontier Foundation also noted that "due to the fact that canaries are non-standard makes it difficult to automatically monitor them for changes or takedowns".