I have a ziped file, but everytime I try to unzip it it asks me for a
password.  It tells me that the files in the folder are password
protected.  The files in the folder are notepad files.  I need
information on how I can open these password protected files.  I need
this ASAP.  I don't have the password, but I need detailed
instructions on how to hack my files.

---

Request for Question Clarification by chromedome-ga on 10 Jun 2002 19:32 PDT

Which version of winzip are you using, and on which version of Windows? 

Hi answerdude!!

I had the same problem in the past and I solved it with a software.
But before I give you the solution that I found, you must know some
facts.

At the moment there isnīt known method to extract the password from an
protected zip file. The only available way to recover it is using a
"brute-force" attack. Undocumented features of ZIP files provide a
great time reduction while searching the password with an appropiate
software and the right settings.

Now we can start to recover the password.
There are a lot of password recovery software, but I will recommend to
you the ones that I consider the best.

First the software that I use:

- Advanced Archive Password Recovery (for ZIP, ACE, RAR and ARJ files)
 
Four programs in one -- an ultimate tool to recover lost or forgotten
passwords for ZIP (PKZip/WinZip), ARJ, RAR and ACE archives. Supports
the customizable "brute-force" attack, effectively optimized for speed
(for ZIP, up to ten million passwords per second on Pentium II);
dictionary-based attack, and very fast and effective known-plaintext
and guaranteed WinZip attacks. Multilanguage interface is provided.

http://www.crackpassword.com/advanced_archive_password_recovery.html

Using this software is very easy:
1-First you must choose the file to unlock.
2-Select the type of attack (usually brute-force.
3-Range tab: select type of characters used in password.
4-Range tab: select range (if you know or remember that your password
has four or more characters and it starts with "nick" you must put
nick in the start from box to accelerate the process and put nothing
in end at box).
5-Lenght tab: select the estimated lengh of password.
6-Click on Start Button and wait
If the length of the password is more than seven characters it could
be take more than one hour to find the password, and closer you set
the length, the range and the types of characters used faster you can
unlock the file.

For example to find the password "jhonny" (without quotes)it takes a
little less than a minute, starting with no range length from 3 to 8
characters and only  small latin chars (a-z). If you range it with
START FROM "jhaaaa" (knowing that the password has six chars) it takes
1.472 seconds!!

This software has a trial version with limitations (maximum 5 chars in
password), you can buy the registered version for $60.

Other software:

- ZIP Password Recovery Processor (only ZIP files)
http://www.zipcure.com/zippasswordcracker.html

It is a very good option for only $30, but works with ZIP files only.


- Zip Key
http://www.lostpassword.com/zip.htm#shot

You must register paying $45.



You also can send the files to companies which will do the job for
you. But the price of one password is closer to the price of the
software:

- Password Bully 
Specialize in recovering lost or forgotten passwords.
http://www.passwordbully.com/index.htm

- Alpine Snow 
Online Password Recovery Service.
https://www.alpinesnow.com/upload.cgi


In both cases you must send the files to the companies and then they
will try to find the password, only if they can do it you must pay.


If you more information related to the password recovery:

ZipUnlock.com (A guide to recover your passwords)
http://www.zipunlock.com/sld001.htm

Open Directory - Computers: Security: Products and Tools: Password
Recovery
http://dmoz.org/Computers/Security/Products_and_Tools/Password_Recovery/


I hope this will help you

Regards
livioflores-ga

---

Clarification of Answer by livioflores-ga on 10 Jun 2002 22:42 PDT

I forgot the search strategy: 
 
Keywords: 
Password Recovery 
Password Recovery and "zip files" 
Search engine: Google of course. 
 
Thank you for ask to Google Answers 
livioflores-ga  

The reason why I am unsatisfied with this answer is because he did not
answer my question.  I said the file I need to unlock is in the zip
file.  But he just told me how to unlock a zip file.  Non the less, I
still tried his software and instructions, waisted about 2 hours doing
it, and I still could not open my password protected files.  I want a
refund because my question was not answered correctly.

You may want to try this freeware program first:

ZIP Password Finder
http://www.astonsoft.com/prod3.htm
"ZIP password finder is a completely free tool to recover zip archive
passwords. A lot of functions/attacks, a nice easy to use interface
and $0 price make it the best choice for .zip password recovery."

Nice catch milesw!!

I just tested the soft and it works fine, a little slow but acceptable. 
Try it answerdude and use the tips that I gave you to set the search.

Good luck!!

It is probably of little use to you now, but the encryption used in
PkZip at least(i assume it is the same situation in WinZip) is
vulnerable to a technique called 'Differential Cryptanalysis'. 
However you need to know a small amount of the original
file(plaintext).

I found a site which appears to have an implementation of this
algorithm with binaries for various platforms.  The downside is you
appear to need a second zip archive with ONE of the encrypted files in
the original archive in unencrypted form.  In other words if you have
an encrypted archive of 100 files but you have the original of one of
them, then you can recover all 100.

See http://www.unix-ag.uni-kl.de/~conrad/krypto/pkcrack.html for
further details.

Hope this may help.