An HTTP Status Code to Report Legal Obstacles

An HTTP Status Code to Report Legal Obstacles Textuality

tbray@textuality.com http://www.tbray.org/ongoing/

Applications HTTP This document specifies a Hypertext Transfer Protocol (HTTP) status code for use when resource access is denied as a consequence of legal demands. Discussion of this draft takes place on the HTTPBIS working group mailing list (ietf-http-wg@w3.org), which is archived at . Working Group information can be found at and ; source code and issues list for this draft can be found at .

This document specifies a Hypertext Transfer Protocol (HTTP) status code for use when a server operator has a received a legal demand to deny access to a resource. This status code may be used to provide transparency in circumstances where issues of law or public policy affect server operations. This transparency may be beneficial both to these operators and to end users. discusses the forces working against transparent operation of the Internet; these clearly include legal interventions to restrict access to content. As that document notes, and as Section 4 of states, such restrictions should be made explicit. Feedback should occur on the ietf-http-wg@w3.org mailing list, although this draft is NOT a work item of the IETF HTTPbis Working Group.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in .

This status code indicates that the server is denying access to the resource as a consequence of a legal demand. The server in question may not be an origin server. This type of legal demand typically most directly affects the operations of ISPs and search engines. Responses using this status code SHOULD include an explanation, in the response body, of the details of the legal demand: the party making it, the applicable legislation or regulation, and what classes of person and resource it applies to. For example:

HTTP/1.1 451 Unavailable For Legal Reasons Content-Type: text/html <html> <head><title>Unavailable For Legal Reasons</title></head> <body> <h1>Unavailable For Legal Reasons</h1> <p>This request may not be serviced in the Roman Province of Judea due to the Lex Julia Majestatis, which disallows access to resources hosted on servers deemed to be operated by the People's Front of Judea.</p> </body> </html> The use of the 451 status code implies neither the existence nor non-existence of the resource named in the request. That is to say, it is possible that if the legal demands were removed, a request for the resource still might not succeed. Note that in many cases clients can still access the denied resource by using technical countermeasures such as a VPN or the Tor network.

The 451 status code is optional; clients cannot rely upon its use. It is possible that certain legal authorities may wish to avoid transparency, and not only demand the restriction of access to certain resources, but also avoid disclosing that the demand was made.

The HTTP Status Codes Registry should be updated with the following entries: Code: 451 Description: Unavailable for Legal Reasons Specification: [ this document ]

&rfc2119; &rfc4084; &rfc4924;

Thanks to Terence Eden, who observed that the existing status code 403 was not really suitable for this situation, and suggested the creation of a new status code. Thanks also to Ray Bradbury. The author takes all responsibility for errors and omissions.