Mar 092013
 

Steganography is the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message, a form of security through obscurity. The word steganography is of Greek origin and means “concealed writing” from the Greek words steganos (στεγανός) meaning “covered or protected”, and graphei (γραφή) meaning “writing”. The first recorded use of the term was in 1499 by Johannes Trithemius in his Steganographia, a treatise on cryptography and steganography disguised as a book on magic. Generally, messages will appear to be something else: images, articles, shopping lists, or some other covertext and, classically, the hidden message may be in invisible ink between the visible lines of a private letter.

And now that we have saw the definition of this word, let’s take a look at three open source programs for Linux that you can use to play with this concept: Steghide and Outguess and one closed source Steg

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Dec 022012
 

Logging is a critical thing for all system administrators, if you log too much and you don’t manage the files you could fill up a partition or even worst stop some service, if you don’t log enough you’ll lose information when something goes wrong, in general a good solution for this is to send all the logs to a central server that will store for the time you need them, and keep just 1,2 days of log into the local machine.

You could do this configuration easily with rsyslog or syslog-ng to send/receive the logs and logrotate to rotate the files locally on your machines, today I want to show you some open source programs that can receive the logs, store them on filesystem or database and analyse them presenting the results via Web dashboards.

These are large applications most suited for big company, or in general to everyone that want to keep and manage a lot of data they are: Apache Flume, Logstash, Greylog2 and Scribe

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