What does 'Unk:' mean in 'Stored' column of `unzip -v` output?

Running unzip -v archive1.zip, where archive1.zip is an encrypted archive, I get the following output:

Archive: archive1.zip Length Method Size Cmpr Date Time CRC-32 Name
-------- ------ ------- ---- ---------- ----- -------- ---- 0 Stored 0 0% 2019-11-16 23:24 00000000 archive1/
114313805 Unk:099109732086 4% 2019-11-16 22:44 1ef985bf archive1/1.mp4
105319429 Unk:099101084312 4% 2019-11-16 22:44 eebbbde7 archive1/2.mp4
107103758 Unk:099102799257 4% 2019-11-16 22:45 dee65163 archive1/3.mp4
85603336 Unk:09982215648 4% 2019-11-16 21:56 84f52e69 archive1/4.mp4
84173403 Unk:09981781201 3% 2019-11-16 21:57 4b98d940 archive1/5.mp4
99122800 Unk:09996280568 3% 2019-11-16 21:58 3845f6eb archive1/6.mp4
140263355 Unk:099136233079 3% 2019-11-16 22:00 31aa4007 archive1/7.mp4
136174590 Unk:099130823455 4% 2019-11-16 22:00 17591821 archive1/8.mp4
78035332 Unk:09974880674 4% 2019-11-16 22:01 774c2a37 archive1/9.mp4
65603509 Unk:09963086668 4% 2019-11-16 22:02 6440490e archive1/10.mp4
80659649 Unk:09977446195 4% 2019-11-16 22:03 fa00ff0e archive1/11.mp4
104755598 Unk:099101751952 3% 2019-11-16 22:03 56d38761 archive1/12.mp4
76602784 Unk:09973535589 4% 2019-11-16 22:04 86036941 archive1/13.mp4
77177317 Unk:09974087488 4% 2019-11-16 22:05 67dc781b archive1/14.mp4
94371918 Unk:09994326744 0% 2019-11-16 22:06 451ad487 archive1/15.mp4
64995734 Unk:09962474109 4% 2019-11-16 22:06 cf39a151 archive1/16.mp4

I'm going to try to crack it using bkcrack (I have some videos that are possibly recorded from the same camera, so I can use the video container header as known bytes). However, for such an approach I need to know what do Unk:09... values mean and, speaking more broadly, what software was used to create the archive (multiple options are also OK).

1 Answer

UNK just means your file is AES encrypted.

This answer might help

If it turns out you do have AES encryption and you need a python way to read the file, the standard zipfile approach will not work. As things stand zipfile only supports weak encryption. For other python ways to read AES-encrypted Zip files see Python unzip AES-128 encrypted file