Forgot password

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sdgv dfff
2008-05-01
2012-12-07
  • sdgv dfff
    sdgv dfff
    2008-05-01

    I forgot password. Remember only it consists 5 symbols. All letters except second one that is "2". Can anybody help me?
    Please in any case don't make such advices - http://sourceforge.net/forum/message.php?msg_id=3958896

     
    • dos386
      dos386
      2008-05-02

      > All letters

      UPPER ? lower ? MiXEd ?

      > except second one that is "2". Can anybody help me?

      So we have to guess 4 chars only ... so brute-force through 26^4 = 456976 or 52^4 = 7311616 PWD's ... doable, the problem is that no public 7-ZIP brute-forcer exists.

      > Please in any case don't make such advices

      This type of problem can't be answered "better" ... what did you expect ?

       
    • Yutaka Sawada
      Yutaka Sawada
      2008-05-08

      I made a sample brute-forcer to test speed with general archiver dll.
      Sample archive is only 64 bytes, not compressed, and password is 3 characters.

      I test with my low power PC (Pentium 800MHz).
      Against traditional ZIP encrypted file,
      it can try upto about 2000 passwords per second.
      But, against 7-Zip encrypted file,
      it can try 4 or 6 passwords per second.

      I think it may try only 1 password per second against general file.
      If I make a custom brute-forcer for your specific archive,
      it may more fast, but I can not say in fact.

      My advice is that, remember as possible as you can.
      It is "a to d" or "e to g", upper ot lower etc.
      Or, it is not "a to d"...
      As you remember more, possible passwords will be fewer.
      If you want, I can send my sample brute-forcer with source code.
      It is very slow, but still faster than your typing speed.

       
    • dos386
      dos386
      2008-05-08

      > Against traditional ZIP encrypted file,

      PKZIP 2.xx "crypto" ?

      > it can try upto about 2000 passwords per second.

      COOL. ELCOM can test many 1'000'000 pwd's per second :-D

      > it can try 4 or 6 passwords per second.

      Igor's 256Ki of SHA-256 hashes ;-)

       
      • Igor Pavlov
        Igor Pavlov
        2008-05-08

        - Igor's 256Ki of SHA-256 hashes ;-)

        7-Zip 4.58 uses 512Ki iterations. And I can increase it in future, if it will be required.

         
    • dos386
      dos386
      2008-05-09

      > 7-Zip 4.58 uses 512Ki iterations.
      > And I can increase it in future, if it will be required.

      Without breaking compatibility ? Crypted archive contains the number of them ? It causes a noticable delay  ... further massive increasing would cause problems :-|

       
      • Igor Pavlov
        Igor Pavlov
        2008-05-09

        7zAES properties contains the number of iterations. Check "method" column for encryped file:
        7-Zip 4.57: 7zAES:18
        7-Zip 4.58: 7zAES:19
        So I can double the complexity each 2-3 years.