Your browser identified itself as a version of IE that was often shipped with default settings that were less than secure. Your internet experience could be made more secure by opening Internet Options in your browser, going to the Advanced tab and looking under the security settings for "Use TLS 1.1" and "Use TLS 1.2". Ensure these are turned on (checked). Doing so will enable your browser to support a higher quality of encryption on this and other websites. You will still be able to browse this site without turning on support for TLS 1.1 and 1.2, but we will have to use a lower level of encryption to accomodate you. See this question on Stack Exchange's Superuser forum from 2011 for more details keeping in mind the comments about TLS 1.2 non-support were made many years ago, and things have changed since then.

If the support for better cryptography has been turned on for your browser, thank you, and you can safely ignore this advisory.

Browser Security Alert

.ZIP Application Note

PKWARE® introduced the ZIP format in 1989. This new format combined data compression, file management, and data encryption within a portable archive format. ZIP quickly became the accepted industry standard for cross-platform data exchange and efficient data storage. In order to ensure the continued interoperability of the .ZIP file format for all users, PKWARE publishes an Application Note on the .ZIP file format. The APPNOTE provides developers a general description and technical details of the .ZIP specification. This specification is maintained and periodically updated by PKWARE with support from interested industry experts and other users of this format. These changes are intended to include new capabilities in anticipation of the emerging needs of the ZIP community, while ensuring on-going interoperability for ZIP files.

The .ZIP format remains one of the most widely used file formats for cross-platform interoperability. Leading industry standards including the ECMA Office Open XML and the OASIS Open Document Format for Office Applications incorporate ZIP technology. Other major industry standards incorporating ZIP include the JAVA JAR specification, Sharable Content Object Reference Model (ADL-SCORM) and EPUB. These other industry standards are independently maintained by separate organizations that are not affiliated with PKWARE. Please consult with the appropriate authoring group for additional information about their respective specifications.

This APPNOTE specification may be referenced in other specifications that may benefit from this technology providing the authors of those specifications work to ensure the on-going interoperability of this format. Some ZIP technology is covered by patents or pending patents. If your application requires use of ZIP technology that is covered under a patent, PKWARE does provide reasonable and non discriminatory licensing. To submit requests for information or enhancements please email This email address is being protected from spambots. You need JavaScript enabled to view it..

If you would like to be updated on the developing .ZIP standard, please join the PKWARE APPNOTE subscription service. For additional information on the APPNOTE, see our Publication Policy.

Application Note Archives

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