RTF

RTF
Name	RTF
Developers	Microsoft Corporation
Initial release	1987
Latest release	1.9.1 (documented 2008)
Operating system	Microsoft Windows, macOS, Linux
File extension	.rtf
Mime type	application/rtf

RTF

RTF is a proprietary document file format and markup language introduced for cross-application document interchange. It was promulgated by Microsoft Corporation as a method to encode formatted text, graphics, and document structure for exchange among disparate word processors and office suites. The format has been referenced and implemented by many software projects and vendors, influencing standards discussions in forums attended by representatives from IBM, Apple Inc., Sun Microsystems, and other major technology firms.

Overview

RTF encodes document content as a sequence of ASCII and 8-bit control words, control symbols, and groups, enabling representation of fonts, colors, paragraph properties, and embedded objects. Because of its origin at Microsoft Corporation and its relatively simple, human-readable syntax, RTF was adopted for interoperability by products from Corel Corporation, StarDivision, OpenOffice.org, and Google. The format sits among other document standards such as DOC, PDF, HTML, and ODF in the ecosystem of electronic document interchange.

History and Development

RTF was first released by Microsoft Corporation in 1987 to provide a common interchange format for Microsoft Word and third-party applications. Subsequent updates occurred as part of Microsoft Word versioning, with notable additions to object embedding and extended character sets during the 1990s, involving interoperability discussions with vendors like IBM and Apple Inc.. During the late 1990s and early 2000s, projects such as OpenOffice.org and Apache OpenOffice implemented RTF import/export to enable compatibility with documents created in Microsoft Word and other proprietary editors. Industry standardization bodies and open-source communities, including contributors from Red Hat and Debian Project, debated RTF’s role versus XML-based formats such as Office Open XML and OpenDocument Format.

File Format and Syntax

RTF documents are plain text files using a backslash-initiated control word syntax, grouping with braces, and escape sequences to represent special characters and binary data. The format defines control words for font tables, color tables, paragraph styles, and embedded objects such as Windows Metafile and OLE Package objects used by Microsoft Office. Extended character encoding evolved to support code pages and later Unicode via control words that indicate 16-bit character representation. The published RTF specification produced by Microsoft Corporation outlines the grammar and tokenization rules used by parsers implemented in applications like LibreOffice and AbiWord.

Features and Capabilities

RTF supports rich text formatting including font selection, size, style, superscript, subscript, and paragraph alignment, as well as tables, lists, and nested groups. The format permits inclusion of embedded graphics and objects using mechanisms compatible with formats handled by GDI-based systems and PostScript-aware workflows. Features added over time provided support for bi-directional scripts, complex script shaping relevant to languages handled by contributors from Unicode Consortium-aware projects, and linking to external resources for OLE-linked content in Microsoft Office environments.

Security and Vulnerabilities

Because RTF can encapsulate embedded objects and scripts, it has been a vector in targeted attacks and macro-based exploits, often discussed in advisories from groups like CERT Coordination Center and vendors such as Symantec and Kaspersky Lab. Vulnerabilities have involved buffer overflows in parsers within applications like Microsoft Word and third-party viewers, as well as malicious OLE packages that executed code when documents were opened. Security hardening measures from organizations including Microsoft Security Response Center and recommendations from National Institute of Standards and Technology influenced safer defaults and sandboxing in document processors.

Implementations and Software Support

RTF has been implemented across a wide range of proprietary and open-source software. Notable implementations include Microsoft Word, WordPad, LibreOffice Writer, Apache OpenOffice Writer, Google Docs import/export routines, and lightweight viewers embedded in frameworks such as GTK and Qt. Libraries for programmatic handling exist in ecosystems maintained by Python Software Foundation contributors, Perl CPAN modules, and Java libraries distributed by organizations like Apache Software Foundation. Printer drivers and document converters from vendors such as Adobe Systems also provide RTF support in multi-format workflows.

Interoperability and Compatibility

RTF was designed for cross-platform document exchange, but variations in support for tags, extensions, and object formats led to inconsistent rendering among Microsoft Word, LibreOffice Writer, and other editors. Differences in handling table cell borders, nested lists, and font substitution have been chronicled in interoperability tests conducted by entities such as W3C-linked interoperability efforts and vendor interoperability labs. Conversion tools and filters from projects like Pandoc and UnRTF aim to normalize RTF data for conversion to HTML, PDF, ODF, and DOCX.

Legacy and Current Usage

Although newer XML-based standards like Office Open XML and OpenDocument Format have become dominant in many contexts, RTF remains in use for simple document interchange, legacy archives, and as a fallback export/import option in many editors. Organizations with long-term document repositories, including governmental archives and academic libraries such as Library of Congress, continue to encounter RTF files. Software toolchains for email clients, content management systems, and enterprise document workflows often maintain RTF support to preserve compatibility with historical documents and workflows.

Category:File formats