How to tell if ZIP is compressed or not?
#2
im not so familiar with zip2john, why dont you just test it yourself? first plz update zip2john to latest version (my version is 2.0 and i updated it long time ago)

fast test, first line no compression, second line fast compression, as you can see cmplen is "lenght after compressoion, and SHOULD* be significantly lower wenn using compression
* when data is not or bad compressable, like video-files these assumption can be wrong
crc is the crc from the file within the zip, not the zip itself

ver 2.0 0.zip/google-mail.py PKZIP Encr: cmplen=19103, decmplen=19091, crc=5C1551BC ts=6E2C cs=5c15 type=0
ver 2.0 1.zip/google-mail.py PKZIP Encr: cmplen=6422, decmplen=19091, crc=5C1551BC ts=6E2C cs=5c15 type=8

im not quite sure whether the compression is also mentionened in this hash you get, but when hc tells you signature unmatched in seems so
UPDATE
tried some compressions and zip2john always tells type=8 for compression, and these type (0 uncompressed or 8 compressed) you can find in your hashstring, so yeah hahscat can tell whehter your given mode is right or wrong

$pkzip$1*1*2*0*4a9f*4a93*5c1551bc*0*2c*0*
$pkzip$1*1*2*0*1916*4a93*5c1551bc*0*2c*8*
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Messages In This Thread
RE: How to tell if ZIP is compressed or not? - by Snoopy - 01-10-2022, 03:12 PM