CODEWITHSUNDEEP
zipdocxcrc32
whIsrael
whIsrael

Reputation: 27

Pkzip - CRC-32 in Central directory file header

i am searching the internet to find what Fields are calculating by crc-32 of the Central directory file header as mentiond here wiki-zip

enter image description here

as you can see there are some calculation but i don't know what fields are entered to this calculation, the main reason i want to do this is because i want to enter some data to the comment field and still that a docx file(=pkzip) could be open on office 2007+ without the message of corrupted file, i am pretty sure after long research is that it has something to do with the CRC-32 Calculation.

if there are any other ideas i be glad to hear them

EDIT

i now try to hide more info at the extra feild and get that the file is coruptted althought i added the size to the footer

Upvotes: 0

Views: 794

Answers (1)

Mark Adler
Mark Adler

Reputation: 112404

If you are simply inserting a comment in the central directory, then the problem has nothing to do with the CRC. You are messing up the size of central directory in the end of central directory field.

Upvotes: 1

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