terça-feira, novembro 04, 2008

rewind and fastforward

Long time since I posted in this blog. Working & studding is harder than I ever imagined and what I miss the most is time to play around like I used to. Routines settle in... A must do is to know what is going on. So on most mornings and some afternoons and nights like right now. There are a certain number of "must open tabs", made easily accessible by a favourites folder called morning on firefox, (OsNews, SlashDot && publico) swimming on my desktop.

On these last few months I've read more man pages, apis, documentation than in the rest of my life all put together. There are number of things that I am specially excited about like php which has not ceased to surprise me in capacity and flexibility. For instance I was wondering how was I going to make this new app we're developing module customizable, by text file. And I reached the conclusion that it would be most pleasent If I could allocate variables, based on that text file. This seams rather simple. Though it may become a headacke to think of the code with a bunch of ifs and elses, or even on a C style of thinking with IFDEF. The intuitive thing would be like

$var = 'myvarname';
$$var = 'myvarname_value';

this is the same as
myvarname = myvarname_value;

I thought this would be impossible. For my narrow mind limited the idea of a variable as memory space, and thought of running code as compiled code, and therefore....
mov 0x50, #50 kind of thing.

well details.. they are so many.. and my time is rather sparse so I'll get to why I decided to write this post.

Slashdot mentioned an article published on arxiv 'bout steganography. This is a new consept for me. When one ponders on the security of information on the web, one thinks: cryptography. One thinks of dissimulating the message, but one does not think of making the message "disappear". In essence: to think of a way to send the message in such a way that the only the sender and the receiver are capable of recognizing that there is a message going through the channel.

I thought this idea was delightful. If you do too, sharp your eyes and open your mind. The article link is just bellow. ;)

A pleasant night to you reader.

"This work investigates a central problem in steganography, that is: How much data can safely be hidden without being detected? To answer this question, a formal definition of steganographic capacity is presented. Once this has been defined, a general formula for the capacity is developed. The formula is applicable to a very broad spectrum of channels due to the use of an information-spectrum approach. This approach allows for the analysis of arbitrary steganalyzers as well as non-stationary, non-ergodic encoder and attack channels.
After the general formula is presented, various simplifications are applied to gain insight into example hiding and detection methodologies. Finally, the context and applications of the work are summarized in a general discussion. "
REF: arXiv:0810.4171v1