
 UZPC v3.00
 ==========

 Unregistered version notes
 --------------------------
   UZPC will recover only two files from encrypted archive. All other files
 in archive will be invalid. How to register see the file "readme.txt".


 "Known plaintext" attack description
 ------------------------------------

   This version of UZPC supports powerfull "known plaintext" attack.
   This means that if you're have only _ONE_ un-encrypted file from passworded
 archive you can extract _ALL_ files from archive (of course, if its was
 encrypted with same password).
   The basic rules are:
 1. Take un-encrypted file which also present in passworded archive.
 2. Compress it with _SAME_ method and _SAME_ archiver as an encrypted archive.
    Note that this is strongly needed because UZPC checks file sizes and
    checksums of files.
 3. Run UZPC, select encrypted archive, then select "plaintext" attack and
    browse for archive with unecnrypted file. Also define name of unencrypted
    archive that will be created when UZPC find matching keys. After that
    UZPC will checks files and if it find match files it starting to work.

 UZPC starting to work. There are four cycles in "plaintext" attack
 (if you're know something about .zip encrypted scheme you'll undestand
 what I mean, if not just read estimated timings for cycles at K6-2-300):
 1. Generation keys2 and first reduction cycle. At this and next cycle
    you're need about 34 megabytes of (virtual) memory. This cycles takes
    about several minutes.
 2. Main reduction cycle. Also takes several minutes and now you can
    see "progress" indicator. At first it will at 0% for several minutes
    and then it'll starts to increase rapidly. After this cycle memory will
    be freed and UZPC will works with about 2 megabytes only.
 3. Reordering keys2. Takes few minutes. The main aim of this cycle is to
    estimate how long will UZPC works. Note that first three cycles have
    no estimate time. Only "progress" indicator.
 4. Searching matching keys. This is main cycle of "plaintext" attack.
    Now you can see how much time you're need (in worse case) to recover
    archive.

 After UZPC found matching keys it create archive
 "<archive name>_UnEncrypted.zip" (by default)
 which will be un-encrypted and report you about done work.
 You can extract files from this archives with any .zip archiver.

 Current version notes
 ---------------------
 1. You can't define binary file as "plaintext" file. In next version we'll
    add this ability but usually you're need in whole un-encrypted file
    (if attacked file was deflated).
 2. "Plaintext" file must be at least 40 bytes long.
 3. "Plaintext" attack cannot be saved. But when we're testing "plaintext
    attack" engine we'd see that you're need from 15 minutes to 4-8 hours
    to recover archive (check your luck :-) )
 4. No estimate time for first three cycles. But you can expect that its
    takes only several minutes.
 5. In any case you're need about 34 megabytes of RAM. If you haven't so
    much (is this so much? :-) ) RAM you're need enough swapspace on disk.
 6. May be you're think that "plaintext" attack doesn't contains some 
    usefull abilities. In this case, please contact to us and we'll try to
    add this feature to UZPC.

 Test results
 ------------
    Usually recovering process takes about one hour (at K6-2-300 system). You
  can expect this time if you're using "plaintext" file which length is greater
  then 4-6Kb. But in unlucky case UZPC will recover archive for longer time.
    When we're testing "plaintext attack" engine we've got 15 minutes working
  time for archive with 6Kb "plaintext" file and 4 hours (of 8) for archives
  with 32Kb "plaintext" file.


 Thanks for reading this file.
 If you're have any questions about UZPC, please feel free to contact us
 via e-mail: trooper@mail.wplus.net.

