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WinZip and PKZip no longer compatible

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  • WinZip and PKZip no longer compatible

    According to an article on ZDNet (, zip files using the new security extensions from WinZip and PKWare aren't compatible, but both continue to use the ".zip" extension. Will AMS be able to tell the difference? Has anybody written any code to tell the difference and launch the right utility?

  • #2
    Re: WinZip and PKZip no longer compatible

    Well this is going to be a problem for all of us in the future. For not only is ZIP now becoming available in 3 varieties. ACE is in 2 varieties version 1.x and 2.x, their problem is no backwards compatible. Then there is winRAR 3.0 that has the password bug in it. Then there is ACDZip that can't open some RAR files correctly.
    So what does that leave us. Not very much. I feel that we as users can't expect APMS to sort out these problems by hard coding. Thus that leaves us the users to write better code.
    Now thinking about this problem (because I use a lot of ZIP's), I feel that in theory we would have to test the file first with one version of zip, and if we get an error code then test it again with another version of zip, and so on. This would mean that we would have to have each version of ZIP; ACE and maybe RAR on our CD Rom. Now I feel that this is not going to work out to well.
    So maybe there may be a way to read the ZIP header to find out what version it is, though I have not gotten around this problem yet (working with JPG's) with out having user interaction. So it may come down to the point that we can't open other peoples ZIPed files. I use PassWorded ZIP files stored on my CD Rom, so I know that they are safe, the standard type.
    As the article stated there is not much call for ZIPed files anymore, hopefully this will become the norm though I don't believe so. If things become much worst then maybe SelfExtracting archives could become the norm.


    • #3
      Re: WinZip and PKZip no longer compatible

      If crucial performance is an issue then a self extractor is a good solution, I agree. I like .zip files, too bad the thng is going sideways... Can't we all just get along?

      Corey Milner
      Creative Director, Indigo Rose Software


      • #4
        Re: WinZip and PKZip no longer compatible

        In practice, this won't be too much of a problem at all, unless your AutoPlay application needs to extract files from Zip archives that the user provides at run time. I don't imagine that is a very common thing. [img]/ubbthreads/images/icons/smile.gif[/img]

        Since you will almost certainly always be the one adding the zips to your project, just make sure they are in the format that AutoPlay can read. AutoPlay has its own Zip extraction engine built in; it doesn't use winzip or pkzip or anything else on the user's system. (Well, it could if you used a File.Execute or File.Open action to open it externally, but that's beside the point.)

        So just make sure you create your password-protected Zip files using the appropriate compatible tool and you will be fine.

        Note: from a security standpoint, it's actually in your favor if the user's Zip utility is incompatible with your password-protected Zip file.
        --[[ Indigo Rose Software Developer ]]


        • #5
          Re: WinZip and PKZip no longer compatible

          Good point about the security benefit of incompatibilities. However, what zip utilities (and versions thereof) is AMS' built-in extraction engine compatible with? If the AMS extraction engine was created before the latest versions of WinZip and PKZip were released, the security extensions could still potentially be a problem.

          As an aside, I think password-protected zip files are going to become standard practice. For example (not that it really applies to CDs), our corporate behemoth parent just changed its email system to delete zip attachments unless they're password protected. Apparently there's some kind of virus or worm that can infect zip files. If corporate clients start taking drastic measures against zip files and executables (which is what a self-extracting archive is), it could be a problem even for stuff launched from a CD.