[
  {
    "Id": "646065",
    "ThreadId": "266200",
    "Html": "\r\n<p>I am trying to unzip a file that uses&nbsp;<span style=\"color:black; font-size:10pt\"> AES128 encryption.&nbsp; I try passing the password in code but I keep getting an error that&nbsp; *.zip uses an unsupported compression method.&nbsp; Can I not unzip this\r\n file using dotnetzip?</span></p>\r\n<p><span style=\"color:black; font-size:10pt\">&nbsp;</span></p>\r\n",
    "PostedDate": "2011-07-22T05:41:56.883-07:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  },
  {
    "Id": "646488",
    "ThreadId": "266200",
    "Html": "<p>From the error message, probably not.</p>\r\n<p>What is the exact error message you see?</p>\r\n<p>AES encryption is distinct from the compression method.&nbsp; In a zip file, entries can be encrypted, or compressed, or both.&nbsp; For encryption, DotNetZip handles PKZIP encryption or AES encryption.&nbsp; There are other encryption possibilities in zip files, which DotNetZip does not handle.&nbsp; For compression, DotNetZip handles DEFLATE.&nbsp; There are other compression methods that DotNetZip does not handle (eg, BZIP2, others).&nbsp;</p>\r\n<p>It's possible that you have a zip file that is compressed with a compression method that is not supported by DotNetZip (eg BZIP2) and then encrypted with AES128.&nbsp; In that case DotNetZip would not be able to extract the entries.</p>\r\n<p>&nbsp;</p>",
    "PostedDate": "2011-07-23T07:23:28.637-07:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  },
  {
    "Id": "646821",
    "ThreadId": "266200",
    "Html": "<p>Thanks for the reply.&nbsp; The message I get is Entry db.bak uses an unsupported compression method (0x09, Deflate64)&nbsp; I am kind of at a loss here how to do this programatically.</p>",
    "PostedDate": "2011-07-24T13:03:38.72-07:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  },
  {
    "Id": "647186",
    "ThreadId": "266200",
    "Html": "<p>DotNetZip does not support <a href=\"http://en.wikipedia.org/wiki/DEFLATE#Deflate64.2FEnhanced_Deflate\">DEFLATE64</a>.&nbsp;&nbsp;&nbsp;It has nothing to do with encryption, or passwords, or AES128. DEFLATE64 is a compression method.</p>\r\n<p>DotNetZip cannot extract entries in a zip file that are compressed with DEFLATE64.&nbsp; Once I looked into adding this capability into DotNetZip, but DEFLATE64 is proprietary, specified only by PKWare, and I think it is not well-supported or broadly used.&nbsp; So I decided to not try to do the work.</p>\r\n<p>(ps: not that you asked, but since I mentioned bzip2.... I thought I would add here for posterity's sake&nbsp;that I am right now working on adding BZIP2 compression to DotNetZip.&nbsp;&nbsp; Unlike Deflate64, BZip2 is not proprietary; it is broadly supported;&nbsp;and it is broadly used elsewhere (though used less commonly within ZIP files).&nbsp;&nbsp;&nbsp;The BZIP2 compressor is currently working nicely, and tests with WinZip show that it is fully compatible.&nbsp; but I haven't produced a binary release with this, yet. The first release with the bzip2 capability will be v1.9.1.6.&nbsp;Coming soon.)</p>",
    "PostedDate": "2011-07-25T07:31:35.333-07:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  },
  {
    "Id": "1127103",
    "ThreadId": "266200",
    "Html": "Guys,\r<br />\n<br />\nI get the same error message:\r<br />\nEntry FBN_BETALING_20130628.csv uses an unsupported compression method (0x09, Deflate64)\r<br />\n<br />\nI don't get it, I zip a bunch of files from a directory with the windows send to compressed folder way.\r<br />\n<br />\nDoes windows uses DEFLATE64??<br />\n",
    "PostedDate": "2013-11-20T07:44:28.23-08:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  },
  {
    "Id": "1202571",
    "ThreadId": "266200",
    "Html": "I get the same Deflate64 error as well.  My client is using windows explorer - Send to (compressed) zipped folder.  When I use either the 4.5 .Net Framework or DotNetZip utility, I get the same non supported Deflate64 error.  I checked the machines where the files are being zipped, thinking that maybe the .zip extension was associated with a 3rd party compression application, but that's not the case.\r<br />\n<br />\nOne guess is that the error message is bogus and the real reason has to do with the size of the file being extracted.  In my case, it's over 2 gig in size.\r<br />\n<br />\nJust noticed how old the prior post is.  Regardless, there's still no resolution to the prior post, or is there?<br />\n",
    "PostedDate": "2014-02-04T09:10:50.503-08:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  }
]