Network Working Group L. McIntyre Request for Comments: 3950 Consultant Obsoletes: 3250 G. Parsons Category: Standards Track Nortel Networks J. Rafferty Brooktrout Technology February 2005
Tag Image File Format Fax eXtended (TIFF-FX) - image/tiff-fx MIME Sub-type Registration
Status of this Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This document describes the registration of the MIME sub-type image/tiff-fx. The encodings are defined by File Format for Internet Fax and its extensions.
This document describes the registration of the MIME sub-type image/tiff-fx. The encodings are defined by File Format for Internet Fax [TIFF-FX] and its extensions.
This document is a product of the IETF Internet Fax 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 BCP 14, RFC 2119 [REQ].
Tag Image File Format Fax eXtended (TIFF-FX), is defined in detail by RFC 3949, "File Format for Internet Fax" [TIFF-FX].
McIntyre, et al. Standards Track [Page 1]
RFC 3950 image/tiff-fx February 2005
While a brief scope and feature description is provided in this section as background information, the reader is directed to the original TIFF-FX specification (File Format for Internet Fax) to obtain complete feature and technical details.
This document defines a TIFF-based file format specification for enabling standardized messaging-based fax over the Internet. It specifies the TIFF fields and field values required for compatibility with the existing ITU-T Recommendations for Group 3 black-and-white, grayscale and color facsimile. TIFF has historically been used for handling fax image files in applications such as store-and-forward messaging. Implementations that support this file format specification for import/export may elect to support it as a native format. This document recommends a TIFF file structure that is compatible with low-memory and page-level streaming implementations.
Unless otherwise noted, the current TIFF specification [TIFF] and selected TIFF Technical Notes [TTN1, TTN2] are the primary references for describing TIFF and defining TIFF fields. This document is the primary reference for defining TIFF field values for fax applications.
This document defines the image/tiff-fx MIME sub-type to refer to TIFF-FX Profiles J, C, L and M encoded image data and any future TIFF-FX extensions, or a subset. The image/tiff-fx content type MAY be used when black-and-white image data is encoded using TIFF-FX Profiles S or F, or a subset, however, the image/tiff content type SHOULD be used.
To: ietf-types@iana.org Subject: Registration of Standard MIME media type image/tiff-fx
MIME media type name: image
MIME subtype name: tiff-fx
Required parameters: none
Optional parameters: none
Encoding Considerations:
This media type consists of binary data. The base64 encoding should be used on transports that cannot accommodate binary data directly.
Security considerations:
TIFF-FX utilizes a structure which can store image data and attributes of this image data. The fields defined in the TIFF-FX specification are of a descriptive nature and provide information that is useful to facilitate viewing and rendering of images by a recipient. As such, the fields currently defined in the TIFF-FX specification do not in themselves create additional security risks, since the fields are not used to induce any particular behavior by the recipient application.
TIFF-FX has an extensible structure, so that it is theoretically possible that fields could be defined in the future which could be used to induce particular actions on the part of the recipient, thus presenting additional security risks, but this type of capability is not supported in the referenced TIFF-FX specification. Indeed, the definition of fields which would include such processing instructions is inconsistent with the goals and spirit of the TIFF-FX specification.
The MIME type and file extension defined by this document MUST NOT be used to blindly select a processing program. It is up to the implementation to determine the application (if necessary) and render the image to the user.
McIntyre, et al. Standards Track [Page 3]
RFC 3950 image/tiff-fx February 2005
Interoperability considerations:
The ability of implementations to handle all the defined applications (or profiles within applications) of TIFF-FX may not be ubiquitous. As a result, implementations may decode and attempt to display the encoded TIFF-FX image data only to determine that the image cannot be rendered.
Published specification:
TIFF-FX (Tag Image File Format Fax eXtended) is defined in:
RFC 3949, "File Format for Internet Fax", February 2005, Buckley, R., Venable, D., McIntyre, L., Parsons, G., and J. Rafferty.
Applications which use this media type:
Imaging, fax, messaging and multi-media
Additional information:
Magic number(s): II (little-endian): 49 49 2A 00 hex MM (big-endian): 4D 4D 00 2A hex File extension(s): .TFX Macintosh File Type Code(s): TFX
Person & email address to contact for further information:
TIFF-FX utilizes a structure which can store image data and attributes of this image data. The fields defined in the TIFF-FX specification are of a descriptive nature and provide information that is useful to facilitate viewing and rendering of images by a recipient. As such, the fields currently defined in the TIFF-FX specification do not in themselves create additional security risks, since the fields are not used to induce any particular behavior by the recipient application.
TIFF-FX has an extensible structure, so that it is theoretically possible that fields could be defined in the future which could be used to induce particular actions on the part of the recipient, thus presenting additional security risks, but this type of capability is not supported in the referenced TIFF-FX specification. Indeed, the definition of fields which would include such processing instructions is inconsistent with the goals and spirit of the TIFF-FX specification.
The MIME type and file extension defined by this document MUST NOT be used to blindly select a processing program. It is up to the implementation to determine the application (if necessary) and render the image to the user.
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