data with people using competing software. The fact that the user depends on a particular brand of software to retrieve the information stored in a proprietary format file increases barriers of entry for competing software and may contribute to vendor lock-in concept. The issue of risk comes about because proprietary formats are less likely to be publicly documented and therefore less future proof. If the software firm owning right to that format stops making software which can read it then those who had used the format in the past may lose all information in those files. This is particularly common with formats that were not widely adopted. However, even ubiquitous formats such as Microsoft Word cannot be fully reverse-engineered. Prominent proprietary formats Open proprietary formats AAC – an open standard, but owned by Via Licensing GEDCOM – an open specification for genealogy data exchange, owned by the Church of Jesus Christ of Latter-day Saints MP3 – an open standard, but subject to patents in some countries Closed proprietary formats CDR – (non-documented) CorelDraw's native format primarily used for vector graphic drawings DWG – (non-documented) AutoC AD drawing PSD – (documented) Adobe Photoshop's native image format RAR – (partially documented) archive and compression file format owned by Alexander L. Roshal WMA – a closed format, owned by Microsoft Controversial RTF – a formatted text format (proprietary, published specification, defined and maintained only by Microsoft) SWF – Adobe Flash format (formerly closed/undocumented, now partially or completely open) XFA – Adobe XML Forms Architecture, used in PDF files (published specification by Adobe, required but not documented in the PDF ISO 32000-1 standard; controlled and maintained only by Adobe) ZIP – a base version of this data compression and archive file format is in the public domain, but newer versions have some patented features Formerly proprietary GIF – CompuServe's Graphics Interchange Format (the specification's royalty-free licence requires implementers to give CompuServe credit as owner of the format; separately, patents covering certain aspects of the specification were held by Unisys until they expired in 2004) PDF – Adobe's Portable Document Format (open since 2008 - ISO 32000-1), but there are still some technologies indispensable for the application of ISO 32000-1 that are defined only by Adobe and remain proprietary (e.g. Adobe XML Forms Architecture, Adobe JavaScript). DOC – Microsoft Word Document (formerly closed/undocumented, now Microsoft Open Specification Promise) XLS – Microsoft Excel spreadsheet file format