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WINZIP® AND PKZIP® PASSWORD RECOVERY
WINZIP® and PKZIP® programs feature fairly robust encryption but there are three ways to extract data and passwords from these files.
The first way is by performing a known plaintext attack. A known plaintext attack is accomplished by using an unencrypted version of one of the files in a zip archive to decrypt the others. As an
example, let’s assume that three files are encrypted into an archive using the same password. The client has an exact unencrypted copy of one of the files, but wants the other two. We can then
perform a known plaintext attack on the archive to decrypt not only the other two files, but to acquire the password.
Why, you might ask, would someone want to decrypt an archive if they already have an unencrypted copy of the files? First, a zip archive might contain hundreds or thousands of files. Only one is
needed to perform the known plaintext attack. Frequently archives are created of all of the files on a hard-disk or of all of the files pertaining to a particular project. Some of these files might
be unique and no other copies might exist. However, many files on a computer are very common to other computers (driver files, software files, templates, graphics, icons, etc.) Therefore, one or more
files from an archive might be able to be obtained from another source or might be very common and easily reproduced even if the owner of the zip archive doesn’t have those files. Further, the
password used to encrypt one archive, might be the key to decrypting another archive or another file for which no plaintext exists.
A known plaintext attack is complicated to run, but is usually successful. It will take us a couple of days from the time we receive or find the files. Our regular fee for this type of work is $250.00
(US) for each archive. Please contact us before sending files of more than
1.5 Meg.
The second method is called a dictionary attack. In this attack, passwords from a VERY large list of words in numerous languages, phrases, numbers, names, quotes and other sources of common passwords are used to attempt to guess the password. Multiple combinations of capitalization and combinations of words are tested. Because of the speed of the software programs we use to perform this work, this can be done relatively quickly. We have compiled dictionaries from numerous sources into a single large dictionary which can be used for this type of attack. Typically, people are very similar and most people still choose a word, name or number that is short and easy to remember. This method may provide the password.
The last method is called a brute force attack. In this attack, every possible combination of characters is tested against the password until a match is found. This can take a very long time and this
method will only be successful on short passwords. Some level of enhancement and skill can be added to this method by carefully planning the sequence of guesses and the character sets used. While
this method will eventually be 100% effective, the length of time needed utilizing existing technology can sometimes exceed the age of the universe. While this method is, therefore, only practical
with short passwords, we have had success with this method in the past.
Our fee for attempting the dictionary and brute force attacks is $250.00 (US) if we find your password. If these attempts fail, you pay nothing. Typically we will test our entire dictionary and brute
force passwords up to 7 characters long (a couple of days of processing time though we may recover your password at any time during the process).
As always, our fees are guaranteed, if we fail to decrypt your files or find your password, you have no obligation to pay. If you are interested in having us perform this work please contact us by
email at [email protected]
or toll-free in the United States at 1-877-792-7225 (1-877-PW-CRACK).
If you would prefer to recover Winzip® or Pkzip® passwords yourself, you can purchase Winzip® or Pkzip® password recovery software from Passware, Inc.
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