(last updated 2011-03-28) Type name: text Subtype name: turtle Required parameters: None Optional parameters: charset — this parameter is required when transfering non-ASCII data. If present, the value of charset is always UTF-8. Encoding considerations: The syntax of Turtle is expressed over code points in Unicode [UNICODE]. The encoding is always UTF-8 [RFC3629]. Unicode code points may also be expressed using an \uXXXX (U+0 to U+FFFF) or \UXXXXXXXX syntax (for U+10000 onwards) where X is a hexadecimal digit [0-9A-F] Security considerations: Turtle is a general-purpose assertion language; applications may evaluate given data to infer more assertions or to dereference URIs, invoking the security considerations of the scheme for that URI. Note in particular, the privacy issues in RFC3023 section 10 for HTTP URIs. Data obtained from an inaccurate or malicious data source may lead to inaccurate or misleading conclusions, as well as the dereferencing of unintended URIs. Care must be taken to align the trust in consulted resources with the sensitivity of the intended use of the data; inferences of potential medical treatments would likely require different trust than inferences for trip planning. Turtle is used to express arbitrary application data; security considerations will vary by domain of use. Security tools and protocols applicable to text (e.g. PGP encryption, MD5 sum validation, password-protected compression) may also be used on Turtle documents. Security/privacy protocols must be imposed which reflect the sensitivity of the embedded information. Turtle can express data which is presented to the user, for example, RDF Schema labels. Application rendering strings retrieved from untrusted Turtle documents must ensure that malignant strings may not be used to mislead the reader. The security considerations in the media type registration for XML ([RFC3023] section 10) provide additional guidance around the expression of arbitrary data and markup. Turtle uses IRIs as term identifiers. Applications interpreting data expressed in Turtle sould address the security issues of Internationalized Resource Identifiers (IRIs) [RFC3987] Section 8, as well as Uniform Resource Identifier (URI): Generic Syntax [RFC3986] Section 7. Multiple IRIs may have the same appearance. Characters in different scripts may look similar (a Cyrillic "о" may appear similar to a Latin "o"). A character followed by combining characters may have the same visual representation as another character (LATIN SMALL LETTER E followed by COMBINING ACUTE ACCENT has the same visual representation as LATIN SMALL LETTER E WITH ACUTE). Any person or application that is writing or interpreting data in Turtle must take care to use the IRI that matches the intended semantics, and avoid IRIs that make look similar. Further information about matching of similar characters can be found in Unicode Security Considerations [UNISEC] and Internationalized Resource Identifiers (IRIs) [RFC3987] Section 8. Interoperability considerations: There are no known interoperability issues. Published specification: http://www.w3.org/TeamSubmission/2008/SUBM-turtle-20080114/ Applications which use this media type: No widely deployed applications are known to use this media type. It may be used by some web services and clients consuming their data. Additional information: Magic number(s): Turtle documents may have the strings '@prefix' or '@base' (case dependent) near the beginning of the document. File extension(s): ".ttl" Base URI: The Turtle '@base ' term can change the current base URI for relative IRIrefs in the query language that are used sequentially later in the document. Macintosh file type code(s): "TEXT" Person & email address to contact for further information: Eric Prud'hommeaux Intended usage: COMMON Restrictions on usage: None Author/Change controller: The Turtle specification is the product of David Beckett and Tim Berners-Lee. A W3C Working Group may assume maintenance of this document; W3C reserves change control over this specifications. (file created 2011-03-28)