Skip to main content

Proposed ZIP Format Specification Additions

The items appearing below are proposed for inclusion in the next APPNOTE release.  Please review and post any questions or comments to

Join the discussion online.  Next session is TDB.  Contact for access.

ZIP Source Identifier (PKWARE):

Pending proposal to include a new source identifier record at the front of .ZIP files.  This new data structure will serve to differentiate between vendor applications that create/modify ZIP files.  Modeled after extra field structures this record would likely include:

Marker - 4 bytes TDB

Size - size of remaining record

Data - vendor defined information structure

Problem to solve: a number of ZIP users look for readily available information on what (application/vendor etc) created a given file to assist with feature support determination with less record parsing.


While a vendor marker could be seen as useful for a number of use cases, such as inspection/forensics, it can be an easily circumvented mechanism.  Placing the marker at the front of a ZIP was discussed as desired to support locating it more easily without additional local or central header processing.  Options discussed included ZIP comment or CD.

Authentication method is needed to ensure a reasonable degree of integrity of the marker data, but this info will exist outside of currently signed data.

Interoperability was identified as a potential problem as this marker could be a problem for some ZIP utilities unless they add tolerance.

JavaScript errors detected

Please note, these errors can depend on your browser setup.

If this problem persists, please contact our support.