From time to time I am asked to break a password on an Adobe PDF
file. This mostly comes up when the user who created the pdf can’t
remember what their own password is. As annoying as that is, actually
recovering the password is simple using pdfcrack.
PDFCrack is a GNU/Linux application (or any other POSIX-compatible system) tool for recovering passwords and content from PDF-files. It is small, command line driven, and without external dependencies. PDFCrack is released under GPL.
Install pdfcrack on Ubuntu by typing:
sudo aptitude install pdfcrack
Run a quick benchmark by entering the following at the command line:
pdfcrack -b
Results:
Benchmark: Average Speed (calls / second):
MD5: 2616026.7
MD5_50 (fast): 146928.3
MD5_50 (slow): 107780.3
RC4 (40, static): 863985.7
RC4 (40, no check): 864661.2
RC4 (128, no check): 802203.0
Benchmark: Average Speed (passwords / second):
PDF (40, user): 653588.2
PDF (40, owner): 322317.1
PDF (40, owner, fast): 714278.6Read more..
Password less SSH login to another server can be very useful when
you want to configure a remote backup server or when migrating servers.
For enabling this you need to have openSSH installed on the server.
Here is a tutorial on how to configure password less SSH login to
server ‘mars’ from server ‘earth’
This is a simple article to setup a DNS Server in
Ubuntu. Please follow the steps to make this. Setting up DNS Server is
used to serve the new domain names using your IP. This is kind of providing
webhosting.
Creating your own OS can be quite a daunting task that requires a lot
of computer knowledge. I found a site that may interest you, Custom
NimbleX2 is an open-source project that allows even novices in
computing to create their own Linux OS.
a 
Have you ever just finished something important and all of a sudden
the lights dim, your PC begins to sound like the clothes washer, and
then bam, your work is gone? Been there, done that,
got the t-shirt, right? Maybe I should have taken my watch off before
sticking my hand in that running PC after all.
