I've been researching the version history of PKZIP, the once-popular compression software that gave us the still-popular ZIP file format. There are two important MS-DOS versions of it: v1.10, released in March 1990, which was the latest official version for more than 2.5 years, until v2.04c(?) was released in December 1992.v2.04g, released February 1993, which … Continue reading Will the real PKZ110.EXE please stand up?
The other day, a Twitter user (David Buchanan, @David3141593) posted a message that gained some attention. It has an attached JPEG file, with an image of William Shakespeare. If you save a copy of the JPEG file, and unzip it as if it were a ZIP file, it unzips into the complete works of Shakespeare. … Continue reading About that JPEG/ZIP/Shakespeare hybrid file
The ZIP (PKZIP) compressed file format is organized in a backwards fashion. To unzip a ZIP file, you start by looking for a special byte sequence near the end of it. This is a marker for a data structure (the end of central directory) that points to other data structures that appear earlier in the … Continue reading Corrupting ZIP files