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Encryption Security Programming IT Technology

PKWare and Winzip Reach A Secure Zip Compromise 219

Posted by Hemos from the kind-of-working-together.-sort-of dept.
richard_za writes "Until now the rival compression software vendors PKWare and Winzip have had different (incompatible) ways of password protecting the ZIP format. In a bid to prevent fragmentation of the standard they have agreed to have their software support opening of the other's files. They have however not agreed to support a single standard. PKZip's encryption is RSA-based while Winzip use an AES approach which is fully documented here. The Register is running this story. PKWare has this press release."
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PKWare and Winzip Reach A Secure Zip Compromise More

PKWare and Winzip Reach A Secure Zip Compromise

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  • no difference as far as the user is concerned (Score:4, Insightful)

    by MrRTFM ( 740877 ) on Monday January 26, 2004 @09:04AM (#8086961) Journal
    if either program opens the others files the user wont (and shouldn't have to) give a shit which method is used.

    "As long as it works"

    • Re:no difference as far as the user is concerned (Score:5, Insightful)

      by vasqzr ( 619165 ) <`vasqzr' `at' `netscape.net'> on Monday January 26, 2004 @09:09AM (#8086988)
      What about those people who use a version that isn't the latest and greatest?

      2 standards only cause confusion. Remember the Word 95/97/2000 confusion?

      "Call him back and tell him we need it saved as Word 95!"
      • I don't know abot PKWare's windows zip program (the last time I used it, which was only once, their gui was atrocious) but at least in the case of WinZip, upgrades are free, and the serial numbers haven't changed in aeons, so there is no excuse for not upgrading. It's not like winzip is a huge program.

    • Re:no difference as far as the user is concerned (Score:5, Informative)

      by DrXym ( 126579 ) on Monday January 26, 2004 @10:39AM (#8087538)
      Well yes and no. PkZip seems to have licenced RSA BSAFE for their mechanism which make it less likely you'll see versions of InfoZip that support it (at least fully) because it is more complex and possibly proprietary. So there goes portability. And let's hope it doesn't favour some appallingly slow public key based encryption.


      Whereas WinZip have chosen an off-the-shelf algorithm, a GPL implementation of that algorithm and published the full specs to how they've extended the zip format.


      So a user who knows not about such matters might conclude that PKZip performs like a slug, costs more thanks to licencing or is non-standard while WinZip is none of those things.

  • Ten years too late (Score:5, Insightful)

    by heironymouscoward ( 683461 ) <heironymouscowar ... .com minus punct> on Monday January 26, 2004 @09:04AM (#8086966) Journal
    Zip file management has virtually been absorbed into both Windows and Linux, and even if these two vendors agreed on a standard it would not mean much. PKzip became irrelevant when Infozip's portable zip tool became widely available, around 15 years ago. Further, all archiving tools today already deal with such a variety of formats that I can't see the crying need for a standard.

    • Re:Ten years too late (Score:3, Interesting)

      by f00Dave ( 251755 )
      The issue here isn't with that sort of low level interoperability, but with the schism in the encryption standard used. I haven't checked (in true Slashdot style), but I suspect that Infozip's tool won't handle ZIPs encrypted with recent versions of PK's or WZ's software....

      • Patches are welcome (Score:2, Informative)

        by tepples ( 727027 )

        I suspect that Infozip's tool won't handle ZIPs encrypted with recent versions of PK's or WZ's software....

        That's because Info-ZIP is waiting for volunteers to produce a patch to read and write WinZip's fully documented encryption.

    • Apple has absorbed zip too recently - as of OS X 10.3 zip compression is built into the OS. They look to be moving away from Aladdin's propriatary .sit format...

  • Who's running PKWare (Score:3, Interesting)

    by Anonymous Coward on Monday January 26, 2004 @09:06AM (#8086974)
    Since the PKZip guy killed himself?

  • The issue is encryption standards (Score:5, Insightful)

    by aheath ( 628369 ) * <[adam.heath] [at] [comcast.net]> on Monday January 26, 2004 @09:06AM (#8086975)
    The real issue here is that PKWARE and PKZIP chose to use RSA encryption to secure ZIP files. A digital certificate or a password can be used to encrypt the file. WinZip is use AES encryption to encrypt ZIP files. PKWARE products will now be able to read WinZIP encrypted ZIP files. WinZip products will now be able to read PKWARE encrypted ZIP files.

    There is still a problem with interoperability at the level of creating encrypted ZIP files. There is no longer a problem with interoperability at the level of reading encrypted ZIP files. The best way for this problem to go away would be for PKWARE to expand the SecureZIP standard to include RSA and AES encryption.

    • Both formats still allow you to view the filenames contained within the protected archives, and the only way around that is to zip the protected zip file again to hide this information. This is inelegant - they'd be better off agreeing an improved third standard.

    • Do one thing... (Score:5, Interesting)

      by Ed Avis ( 5917 ) <ed@membled.com> on Monday January 26, 2004 @09:44AM (#8087162) Homepage
      I don't really see why it makes sense for zip and unzip programs to care about encryption. If you want to encrypt the whole archive, it's simple to use GPG on the whole thing. If you want encryption on a per-file basis - again, use GPG on individual files before or after archiving. This is true on Windows too, using whatever your preferred GUI encryption program might be.

      The only reason to stuff both functions into a single program seems to be the perennial problem of installing anything on Windows systems (you can't assume that an encryption tool is available) and marketing - why should users pay $20 twice for two different pieces of tacky shareware when they could pay Winzip $40 for one?
      • That's three pieces of tacky shareware.

        Remember that on Unix-likes, you actually use three tools: tar, gzip and pgp. Zip handles both the file-archiving and file-compression concerns, and now the encryption too.

        I can see definite positives in making it easy for GUI users to create secure compressed archives. It would be nice if there could be three best-of-breed tools that had a united GUI. But that would be cooperation, and that's not the Windows way.
      • It comes down to why you're putting the files into an archive in the first place. If you're just using an archive to transport files from one system to another the classic Unix approach works great.

        But a lot of programs now use archive formats to bundle related files in a single place. Think of Unix archives (.a) files that used to just hold object files in software libraries - now we have Java archives (.jar) files that contain class files and properties, web archives (.war) that contain .jar files, ima

  • Try PowerArchiver (Score:2, Informative)

    by dzorz ( 706431 )
    PowerArchiver is shareware and supports lots of encryption standards (and file formats). Extracted from http://www.powerarchiver.com/features/ >Encryption of files and archives using 5 different methods: Blowfish (128-bit), DES (64-bit), Triple DES (128-bit), AES 128-bit, and AES 256-bit

  • Symmetric vs. asymmetric (Score:5, Interesting)

    by kasperd ( 592156 ) on Monday January 26, 2004 @09:14AM (#8087019) Homepage Journal
    I doubt that PKZip is based only on RSA. RSA is an asymmetric encryption. For some purposes this is nice, but it is inefficient. For that reason you almost always use asymmetric encryption together with a symmetric encryption. You generate a one time symmetric encryption key. The data is encrypted with the symmetric key, typically in CBC or CFB mode. Then only the symmetric encryption key is encrypted asymmetrically, which means much better speed.

    Actually I think this is one of the cases, where there is no need for asymmetric encryption at all. So AES sounds like a better idea. Can anybody explain why PKZip use RSA? And which symmetric cipher is it combined with?

    • Re:Symmetric vs. asymmetric (Score:4, Insightful)

      by hey! ( 33014 ) on Monday January 26, 2004 @09:51AM (#8087212) Homepage Journal
      Actually I think this is one of the cases, where there is no need for asymmetric encryption at all.

      That's only true if you are interested in creating an archive for your own future use. However, if you are interested in exchanging archives with other people, then you have the headache of key exchange, and assymetric encryption is quite useful. Probably most people who need to do this would prefer a solution that handles e-mail and other kinds of documents as well. However if you already have the public key infrastructure in place, it is probably going to be nice to use it for your zip archives too, in a belt-and-suspenders kind of way. I haven't looked at the PKZIP product, but the assymetric encryption should allow for digial signatures on archives as well, which would provide authentication and non-repudiaiton.

      I'd say that the PKZip way would be more attractive to companies that need enteprise wide security and may have built it around RSA, and the WinZip way would be adequate for users who simply want to avoid having people poke around in their files.

    • According to this apge [rarlabs.com], RAR uses AES-128 encryption (see the last paragraph).

    • Re:Symmetric vs. asymmetric (Score:2, Interesting)

      by Anonymous Coward
      I always use asymmetric crypto in my backups.

      This way I do not have to remember or type (i.e. expose) my COMPLEX password each type I make a backup (quite often). Only when I use it (rarely).

      I time factor is irrelevente, in MOST machines, since only a password is incrypted, using GnuPG.
      • I always use asymmetric crypto in my backups.

        Good point. But then you must need to store your key somewhere. Actually each archive you create should contain the secret key encrypted under your password, because you don't want to eventually lose your secret key and then be unable to decrypt your backup copies. So on your harddisk you must keep the encrypted secret key along with the public key. Could you explain in a litle more detail how you do this? And is that the same as PKZip does?
    • With gpg I can encrypt with your key even without asking you to send me your key if it's already in PKI. All I need is your ID in PKI (typically that would be your email) and "ta-da!" - my tar.gz is encrypted and sent by email to you (or published on the web for you). You don't have to know my password or to get any my key - instead you use just your own password to decrypt and (optionally) my ID to verify the signature.

      IMHO bot PKzip and WinZip are sticking their technologies somewhere in mid 90s, while

      • With gpg I can encrypt with your key even without asking you to send me your key if it's already in PKI. All I need is your ID in PKI (typically that would be your email) and "ta-da!"

        Sounds like you don't really "get" PKI then. Would you seriously encrypt an important message using a public key that you received attached to an email?

        How do you know that email from "Alan Cox" with his public key is actually from Alan Cox? The last time you got a penis enlargement spam from "Bill Clinton" did you actuall

        • Sounds like you don't really "get" PKI then. Would you seriously encrypt an important message using a public key that you received attached to an email?

          Sounds like you don't really "get" PKI then. Sending a public key through non-reliable channels is against PKI.

          Well, if your email channel is already protected by signing all content with trusted keys then no problem to trust the key sent through such email.

          Alternatively, I prefer to use keys signed by trusted CA servers.

          When last time have you get s

    • I was actually also suprised to hear they use RSA. How does this even work ? Do you have to get peoples public key before sending them a zip file? While digital signatures are nice, it doesnt make up for the huge inconvenience of having to tailor each zip file for the person you are sending it to.

      The parent is right talking about a combo of asymmetric and symmetric combinations in common use. With SIMP (transparent MSN encryption) the public keys are sent automatically, and you are supped to verify the has
      • Sometimes, you need to send sensitive files among a small workgroup. For example, in the project I work for we have to share files that include confidential information. Asymetric encryption is designed for this kind of thing.
  • .. so it concerns me not a lot. Now if there was a competing 'tar' standard, I'd take more notice :-) Since they've agreed to play nice, this is surely just a "it's ok folks, use whichever you want" moment ? Great. Next.

    Simon
    • um a better equivalent would be gzip. And there is a competing standard to that - bzip :)

      (but they both have their uses. bzip is 'better', but doesn't work on streams like gzip can. It uses blocks.)
      • I thought of that before I posted, but came to the conclusion that I don't really care much about compression any more - the convenience is using a bundle of files rather than that it's 25% of the size of the original...

        Sure, there are times when I will compress something for transfer over the net with time-saving in mind, but this is rare compared to "I have 2500 class files and source files and it needs to be on that machine"...

        Simon

        • Yeah, if it wasn't for the ability to have tar run the archive through b/gzip for me with the -g or -j flag, I would probably just use plain tar files. However, it is convenient enough to just stick the j in, so I bzip all my archives.

          That said, when I used to use Windows, if I needed an encrypted ZIP file, I zipped it up with 7-zip, [7-zip.org] and ran the resulting zip archive through PGP [pgpi.org] to encrypt it. Archiving and encryption are separate. However, a flag for tar to run the final archive (after bzipping) through

    • tar cvO /home/yourfiles | gpg -c > /home/yourfiles.gpg

      Or of course you cuold encrypt to your public key, if you have one setup.

    • Every time someone sends you a zip archive that you need and that doesn't work because you don't have that particular Windows zip program X it will concern and annoy you.
      • Whereas you'll probably be moderated up because my original post seems dismissive, it really doesn't affect me, or to be more accurate, it hasn't ever affected me.

        I use Linux almost exclusively. Even when using windows, I tend to just have VNC onto a linux box. Interoperation with Windows isn't a priority for me, that's all I'm saying...

        Simon
        • But that doesn't change the situation when you receive such an archive. It's even harder to get to its content because you have to switch to Windows for a while, maybe even reboot (if you have only one computer) and install that program.

          If it's not important you can ignore the mail or request an archive in some other format. But there are cases where that's not an option.
    • Not to flame, but do you post on every article that concerns you not a lot?

  • What's good in this? (Score:3, Insightful)

    by Rosco P. Coltrane ( 209368 ) on Monday January 26, 2004 @09:18AM (#8087045)
    In a bid to prevent fragmentation of the standard they have agreed to have their software support opening of the other's files. They have however not agreed to support a single standard. PKZip's encryption is RSA-based while Winzip use an AES

    In other words, the standard is still fragmented, the new thing here is that both software now support both standard fragments, both double in size, and neither is more interesting for the end user than the other.

  • I wonder if 7zip will support both? (Score:5, Informative)

    by Daath ( 225404 ) <(kd.redoc) (ta) (pl)> on Monday January 26, 2004 @09:21AM (#8087060) Homepage Journal
    7zip [7-zip.org] is pretty cool - much better compression than ordinary zip. So I wonder if 7zip will support PKZip/WinZip encryption... From the looks of their fileformat [7-zip.org] page, they support AES encryption...
    Oh yeah and 7zip is under the LGPL license :)
    • Meh use tar/bzip2. That gets better compression than 7zip.

      • Re:I wonder if 7zip will support both? (Score:5, Informative)

        by fredrikj ( 629833 ) on Monday January 26, 2004 @10:18AM (#8087391) Homepage
        Meh use tar/bzip2. That gets better compression than 7zip.

        Well, no. 7zip's 7z format is generally FAR superior to bzip2 in terms of compression ratio.

        A few examples:
        doom2.wad: 14604584 bytes
        doom2.wad.bz2: 5868846 bytes
        doom2.7z: 4560296 bytes

        All MIDI files I've made: 8146186 bytes
        music.tar.bz2: 1007529 bytes
        music.7z: 630357 bytes

        The Python-2.3.2 source code:
        unpacked: 33378982 bytes
        python.tar.bz2: 7216151 bytes
        python.7z: 6034907 bytes

        Those might not even be optimal values. 7z lets you customize a number of parameters (dictionary size, etc) at the expense of compression and decompression speed.

        Also note that the 7z format is modular and can use any compression method supported by the program, including bz2. More info on Wikipedia [wikipedia.org].
    • But until 7zip makes an implementation that runs on some platform other than Windows, I won't be using it for anything. The source code is open, to be sure, but it has so many Windows API calls and hooks that there's simply no way to compile and run it anywhere else without a total rewrite.

  • Merry Poppins Encryption (Score:4, Funny)

    by Anonymous Coward on Monday January 26, 2004 @09:24AM (#8087068)
    They should name the one ecryption scheme:
    Zip-a-dee-do-da

    and the other encryption scheme:
    Zip-a-dee-day

    They could even create new encryption algorithms based on finding the primes of "supercalifragelisticexpealidocious" in various base-N counting systems...

    Ooohhh.. what fun. Makes me want to dance on the rooftops with a bunch of chimney sweeps, seeing songs about PKWare and WinZip... Next thing I know, I'm going to get hired as a Window cleaner...

  • Why bother? (Score:5, Interesting)

    by Ckwop ( 707653 ) on Monday January 26, 2004 @09:31AM (#8087095) Homepage
    I have PGP to encrypt the zip files.. This software has recieved a lot attention and we know that it's probably okay!

    The new standard these guys may agree will have recieved little public analysis when it is fielded.. Not something to trust at all!

    Simon.
    • I have PGP to encrypt the zip files

      What a bizzar combination! Why bother about zip, if you can use along with tar either gzip or bzip?

    • Re:Why bother? (Score:3, Informative)

      by Hatta ( 162192 )
      IIRC PGP/GPG zip their input by default. Less redundancy means better encryption. I just checked my gpg and it uses zlib by default. No point on zipping it twice. Though if you're using bzip2 you'll probably save some space.
      • zlib can be run in stream mode, bzip2 can't. Even if you're willing to operate in block mode (and I'm not sure the OpenPGP specification allows this) the block size of a cipher will be far smaller than the block size of the bzip2 engine.

  • RAR (Score:5, Informative)

    by Jugalator ( 259273 ) on Monday January 26, 2004 @09:32AM (#8087100) Journal
    I couldn't care less about WinZip. WinRAR [rarlabs.com] came in version 3.30 [rarlabs.com] today, for the same price as WinZip and a lot more features. IMHO, it would be better than WinZip even if it didn't support RAR, simply from its arhiver support and features. :-)

    That it happens to use the superior RAR format makes the decision easy for me. We're installing it at our company too, since it isn't even a hard to use archiver for geeks in any way. I know about for example bzip2 and 7-zip, but 7-zip still seems like a rather immature archiver, although it's interesting. The problem is the lack of a good feature set besides the core archiving part. And the official bzip2 package compiled for Windows doesn't come with a GUI so that makes it a bit less useful to me at least, especially when RAR has a comparable compression ratio. Sure, I can use a command line archiver, but I wouldn't like to. :-)

    The only downside I can see is that RAR is a closed source format, with only the decompressor being open.

    Sometimes, I think it's better to not have two different companies trying to get control over a single format. :-P
    • I actively dissuade people from using it. Winzip handles tar.bz2 just fine, so I don't feel bad for pushing that alternative.

      And remember kids, you get the best results when you bzip2 -9!!!
    • The problem is that it is a very uphill battle. Even far superior products fall by the wayside because of established user base. Saving maybe 10% more space & bandwidth and having a slightly better UI isn't enough for most people.

      RAR is used so (relatively) rarely that the download tine and bytes saved by RAR is wasted because I have to find the decomressor, even if I have a local copy.

      I'm not sure if it would save much on the server side because the webmaster would have to deal with complaints that
    • That it happens to use the superior RAR format makes the decision easy for me.

      See how "superior" the RAR format is when you want to extract a single file from the end of a 5 GB archive file.

      ZIP is O(1) -- you can extract that file almost instantly, no matter where in the physical file it resides. RAR is O(n), where n is number of bytes in the archive before the target file -- be prepared for a long wait to get to that file.
  • Course this is what you run into when you build monolithic applications.

  • If the issue is security... (Score:3, Informative)

    by WegianWarrior ( 649800 ) on Monday January 26, 2004 @09:47AM (#8087187) Journal

    ...then both share a common flaw: you have to unpack the container to work on the files within, and that leaves the unpackaged files open to interception.


    I've been using ScramDisk [clara.net] to store my critical data. For those using a newer OS than I do, there is an updated version called DriveCrypt [drivecrypt.com]. Both gves you the choice of what sort of encryption to use and you can use up to four passwords on any given file. It also supports stegnography.


    In short, I don't give a rats ass about what sort of encryption PKZIP or WinZip supports - if the file contains things I want protected, I'll zip it as normal and then drop it into a ScramDisk container.

    • > flaw: you have to unpack the container to work on the files within, and that
      > leaves the unpackaged files open to interception.
      >
      > I've been using ScramDisk to store my critical data.

      Bad news: your files may still be open to interception. When you open them with applications like Photoshop or MS Office or WinZIP, temporary copies are created outside of the container. Usually this is C:\WINDOWS\Temp\ or a temporary folder within your user home directory (for Win2K/XP).

      If your computer

  • Creeping Featurism (Score:5, Insightful)

    by irw ( 204684 ) on Monday January 26, 2004 @09:54AM (#8087244)
    As plugins to existing applications are so popular these days, I see this issue as an irrelevance.

    Both sides are competing using incompatible creeping featurism. Last I looked, Zip applications where supposed to combine and squash files (and that was enough).

    What should be done is to separate the operations:
    - file browsing (WinRAR's interface trumps both)
    - archiving (combining files)
    - compression
    - encryption

    and implement the latter three as functions of the first using plugins (and let the user choose).

    Incidentally, Zip's file format (directory last) sucks. It is practically impossible to do the following using zip:

    tar Bcf - . | gzip -1c | rsh -n over_there gzip -dc | tar -C /path -Bxvf -

    To this end, plugins suggested above should be written as filters where possible.

    I have no problem with browser-like interfaces combining other functions, but the Golden Rule still stands: One Tool, One Job.

    • Re:Creeping Featurism (Score:2, Informative)

      by irw ( 204684 )
      Oops. For the script kiddies that should be:

      tar Bcf - . | gzip -1c | rsh -n over_there 'gzip -dc | tar -C /path -Bxvf -'

      And YES, I know there are Good Reasons why zip has the directory last. I just don't see they're universally necessary.
    • What should be done is to separate the operations:
      - file browsing (WinRAR's interface trumps both)
      - archiving (combining files)
      - compression
      - encryption

      I can see two good cases where combining these funcions ala zip is preferred: random access and dealing with already compressed content. Tar+gzip/bzip sucks from a performance standpoint for random access. Also Zip is at least somewhat intelligent about recognizing and skipping over non-compressible content. If you want random access to encr
      • I should add, it is only creeping featurism if the combination of features working together don't create new functionality. In this case, the advantage you gain is random access to your archive. What you loose is the ability to work with streams.

  • Trapped by pkware! (Score:4, Interesting)

    by Anonymous Coward on Monday January 26, 2004 @09:59AM (#8087270)
    A very dumb company I once worked for chose pkware to archive (and sell) many terabytes of text and images. Unfortunately this was done through a binary only pkware library (for SCO but running on Sequent).. This decision was made around '92 (when many superior alternatives available), before my arrival.

    In the mid-90's they wanted to migrate off of their crap sequent boxes to something better.. Unfortunately, pkware refused to accomodate them by porting the library version to SGI.

    The company was in a bit of a panic as the sequent gear was no longer a viable solution. New customers and scalability problems were rapidly increasing..

    I suggested that they simply decompress on the Sequent and re-compress on the SGI with a better algorithm (source). Forget using pkware. The migration could have been automated such that customer requests resulting in a de-compress would re-file the data in the new system. Requests would check the new servers first. Pretty simple. Batch conversions could occur during off-peak times.

    Nope. Too easy. That would not have been a sufficient crisis.. People would not have looked busy enough.

    The amount of money they were offering pkware finally became sufficient for them to do a version for SGI. So they kept using pkware.

    Oh yeah.. They re-hired the guy who originally decided to use pkware (as a consultant).

  • Unicode (Score:4, Interesting)

    by Midnight Thunder ( 17205 ) on Monday January 26, 2004 @10:03AM (#8087298) Homepage Journal
    A little off topic, but it would be nice if the decided to start supporting unicode filenames in Zip files. With unicode becoming more common in OSs ( this inclues MacOS X, Linux and MS-Windows), I find it ridiculouse that this doesn't even seem to be on their scopes. Well at least it seemed that way when I contacted PKware.

  • Compromise? (Score:3, Funny)

    by mindriot ( 96208 ) on Monday January 26, 2004 @12:17PM (#8088425)
    PKWare and Winzip Reach A Secure Zip Compromise

    Somehow, the word compromise looks wrong in this place... but maybe it describes the security level appropriately? :)

  • Seriously.
  • Just to say, i think stuffit archives are a good alternative. It's for mac and windows, and a lot of mac software is compressed with it. It can do 512-bit security as well as having error correction. Plus it does have better compression (although there is a small performance penalty for it).

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