Blogging

The blog is inactive for a long time and i wish i could post at least one post in three months. I was thinking of few ideas and i missed post them here.

Relationships in Social Networks

i wonder why we spend a lot of time just wandering here and there in online social network sites. i do it though i hate it. This made me to think about do some search on social networks.. still searching on a topic.

i did a small research on relationship named "Link Prediction in Social Networks by Social Distance". The abstract of the paper is as follows,

In the last decade the, Social Networks has been studied extensively in the context of analyzing relationships, interaction between people and determining the interesting structural properties of the network. The studies are mainly focused on online Social Network application such as Facebook, Twitter, LinkedIn and MySpace. The Social Network data in the internet and Application Programming Interfaces (API) enable research on Social Networks. The identification of people who has more probability to be connected, and introduce them to each other enables the network tightly connected and expand the network further. This research is focused on identify the social distance and communities of members in a social network by analyzing structural variable and social variables in to account.


find the full paper here

Display the value of a password fields

If you want to see the value of the password field, it is easily possible to see the
passwords from the browsers like Fire fox and Chrome (i could not find it in IE 6.0).Apart from that i found a Java script that simply shows the typed passwords in password fields in a web page.

What you need to do is copy and paste the following Java script in browser's address bar and click enter.



javascript:(function(){
var s,F,j,f,i;
s = "";
F = document.forms; for(j=0; j{
f = F[j];
for (i=0; i {
if (f[i].type.toLowerCase() == "password") s += f[i].value + "\n";
}
}
if (s)
alert("Passwords in forms on this page:\n\n" + s);

else
alert("There are no passwords in forms on this page.");
})
();

This Java scripts simply reads all the fields that has the "type="password"" sections and read the value.

Refer this article : contents-of-password-field

bqWchpa2JMtot1CZCli8ZhLh0yUb1GU9

Once I completed my B. Sc in Computer Science and Engineering course, I listed a set of subjects that I would never use. All the Electrical, Electronic, Mechanical, Civil and Material Engineering subject were among them. Further, I included Bio informatics, Computer security and Compiler Theory courses, which belong to my major stream .Then I removed the learning materials of those subjects. However, my decision was wrong; I would not have removed Computer Security materials. Okay, lets get in to the topic.

As Wiki says,Blowfish is a
>> Keyed ( Key is the parameter that is used to determine the output of a cryptographic algorithm or cipher ),
>> Symmetric ( The same key is used for both encryption and decryption ),
>> Block cipher (operates on fixed-length groups of bits,),
designed in 1993 by Bruce Schneier. You can find more details from Wiki , so I do not repeat Key Encryption, Encryption, and Decryption details.

I have found two java implementations of Blowfish,

1.Java 2 Platform SE v1.4.2, javax.crypto package
2.GNU blowfish implementation

I have developed a sample application that you can simply start with using 1st implementation. This can be used to encrypt a string using a key (length <=128). The BlowfishEncryptor class API is as follows

/**
* Generates a secret key for a given key size and store in a file. This is
* used only once.
* @param keySize
* Size of the key
* @param fileName
* File name that needs to be stored
*/
public void generateKey(int keySize, String fileName)

/**
* Takes a single String as an argument and returns an Encrypted version of
* that String.
* @param str
* String to be encrypted
* @return String Encrypted version of the provided String
*/
public String encrypt(String str)

/**
* Initializing this object's encrypter and decrypter
* Chipher instances given a secret key file name.
* @param keyFileName
* Secret Key used to identify the key file
*/
public void init(String keyFileName)

/**
* Takes a encrypted String as an argument, decrypts and returns the
* decrypted String.
* @param str
* Encrypted String to be decrypted
* @return String Decrypted version of the provided String
*/
public String decrypt(String str)

The eclipse project is here. I have included a sample Main class to this project as well. To get the topic of this post, copy the current topic and decrypt it using “testKey2” file. Enjoy it :).

Embedded databases for your application

Most of the time people use to go for simpler approaches when they are designing their applications for example using text files to store data. That is perfectly suitable for an application that does not evolve / grow over time. Even though the above factors are violated, still people hesitate to use embedded databases because of simplicity. If you are looking to store data in a text file please reconsider your decision over following facts,
1. Does it grow with time?
2. Is the schema complex?
3. Does application needs flexibility such as merging with other data sources, changing schema or etc ?
4. Does size of the application matter?

Before I read the project proposal of Sip communicator, Chat History Service, I had no idea of embedding a database to our application. After that, I learnt a bit about embedded databases. I developed a sample code that a beginner can start working on SQL embedded databases. I have used apache derby (http://db.apache.org/derby/index.html) database for my sample application.

Apache Derby, an Apache DB subproject, is an open source relational database implemented entirely in Java and available under the Apache License, Some key advantages include:
1. Derby has a small footprint -- about 2 megabytes for the base engine and embedded JDBC driver.
2. Derby is based on the Java, JDBC, and SQL standards.
3. Derby provides an embedded JDBC driver that lets you embed Derby in any Java-based solution.
4. Derby also supports the more familiar client/server mode with the Derby Network Client JDBC driver and Derby Network Server.
5. Derby is easy to install, deploy, and use.

You can download the eclipse sample project that I sent to Sip Communicator. Please go through the manuals and find more details about it. (http://db.apache.org/derby/manuals/index.htm)

Finally I'm there..

I was thinking of creating a blog for months and everyday it had been postponed.. Finally I did accomplish it.. Hmmm.. Lets start from today...