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End: 2023-12

ZIP file format description

Documenting the ZIP file format for reverse engineers and developers

The ZIP file format was originally a compression format, but is meanwhile used a lot in projects. Although there is a historical specification (dating back to 1990), there are plenty of edge cases as well as files not following the specification. These for instance add extra data (electronic signatures/keys, pad data, (an example are Android APK files) or change headers (Dahua firmware files). Information is scattered on various webpages, and can be hard to decipher. The goal is to gather this information in one place and to describe the format properly with examples. Given the broad usage of ZIP files in many use cases by different actors, this will be an ongoing effort - as new exceptions and extensions continue to be uncovered.