(registered 2020-02-12, last updated 2020-02-12)

Type name: application

Subtype name: td+json

Required parameters: None

Optional parameters: None

Encoding considerations: See RFC 6839, section 3.1.

Security considerations: See RFC 8259, section 12.

   Since WoT Thing Description is intended to be a pure data exchange
   format for Thing metadata, the serialization SHOULD NOT be passed 
   through a code execution mechanism such as JavaScript's eval() 
   function to be parsed. An (invalid) document may contain code 
   that, when executed, could lead to unexpected side effects 
   compromising the security of a system.

   WoT Thing Descriptions can be evaluated with a JSON-LD 1.1 
   processor, which typically follows links to remote contexts (i.e.,
   TD context extensions, see W3C WoT Thing Description, section 7) 
   automatically, resulting in the transfer of files without the 
   explicit request of the Consumer for each one. If remote contexts 
   are served by third parties, it may allow them to gather usage 
   patterns or similar information leading to privacy concerns. While
   implementations on resource-constrained devices are expected to 
   perform raw JSON processing (as opposed to JSON-LD processing), 
   implementations in general SHOULD statically cache vetted versions
   of their supported context extensions and not to follow links to 
   remote contexts. Supported context extensions can be managed 
   through a secure software update mechanism instead.

   Context Extensions (see W3C WoT Thing Description, section 7) that
   are loaded from the Web over non-secure connections, such as HTTP,
   run the risk of being altered by an attacker such that they may 
   modify the TD Information Model in a way that could compromise 
   security. For this reason, Consumer again SHOULD vet and cache 
   remote contexts before allowing the system to use it.

   Given that JSON-LD processing usually includes the substitution of
   long IRIs [RFC3987] with short terms, WoT Thing Descriptions may 
   expand considerably when processed using a JSON-LD 1.1 processor 
   and, in the worst case, the resulting data might consume all of 
   the recipient's resources. Consumers SHOULD treat any TD metadata 
   with due skepticism.

Interoperability considerations: See RFC 8259.

   Rules for processing both conforming and non-conforming content 
   are defined in this specification.

Published specification: 

   https://w3c.github.io/wot-thing-description

   Applications that use this media type: All participating entities 
   in the W3C Web of Things, that is, Things, Consumers, and 
   Intermediaries as defined in the Web of Things (WoT) Architecture.

Fragment identifier considerations: See RFC 6839, section 3.1.

Additional information:

   Magic number(s): Not Applicable

   File extension(s): .jsontd

   Macintosh file type code(s): TEXT

Person & email address to contact for further information:
   Matthias Kovatsch <w3c&kovatsch.net>

Intended usage: COMMON

Restrictions on usage: None

Author(s): The WoT Thing Description specification is a product of 
   the Web of Things Working Group.

Change controller: W3C