If a password is too complex to be successfully
discovered via the 'brute-force' method, a second option remains. Since Word
documents (pre-Office XP) are encrypted using 40-bit encryption, it is
actually more efficient to try every single possible 40-bit numerical key than
to attempt to guess a long and complex password, since the number of
variables is smaller.
This method still
takes an extremely long time, regardless of how complex the original password
is, but it is virtually guaranteed to eventually crack the protection.
Unlike the 'password guessing' method, this procedure removes the password
protection entirely. Word for Office XP uses a much greater level of
encryption by default, and thus the 'key matching' method does not work for
Office XP files.
program can be used to decrypt word documents by the simple
expedient of trying every possible numerical key combination until it finds the
correct one. The password protection is then stripped from the
document. This does take a while, though it will almost certainly
work. You will be letting it run for a few days, however. It works
on office 97/2000 Word files and uses the command prompt.
To use GuaWord:
First, make a backup of your
file. This software actually strips the password protection from the file,
and it is possible that the file may be corrupted in the process.
Extract the Guaword.exe file
to a folder on your hard drive. Open the command prompt by going to the
start menu > run > and typing in
Navigate to the location of
the executable file.
'guaword (yourwordfile).doc' to start the
decryption process. Depending on the speed of
your system, decryption will take several days. Unfortunately, your system will
be rather busy while you are running Guaword, so consider using an alternate
computer in the mean time. The same company has a paid version
available which allows you to pause and resume the process.
There are several other
commercial packages available which do the same thing, so if you are looking for
a bit more efficiency than Guaword can offer, shop
Recovering Password Protected ZIP files, and other compressed files
Compressed files with password
protection can be accessed by means of a 'brute-force' password recovery program
that checks all possible character combinations to a certain range, or performs
a dictionary attack. Since most compression programs are capable of
creating various types of compressed files (.zip, .ace, .rar, etc.) most
password recovery programs focus on one of these types, irrespective of the
software that created it.
good example of a freeware Zip password recovery program is the Picozip
Recovery tool by
Softchitect. This easy
to use program performs essentially the same function on .zip files that the
'Free Word and Excel Password Recovery Wizard' does for Microsoft documents.