Kerberos

Kerberos is a network authentication protocol. It is designed to provide strong authentication for client/server applications by using secret-key cryptography. A free implementation of this protocol is available from the Massachusetts Institute of Technology. Kerberos is available in many commercial products as well.
The Internet is an insecure place. Many of the protocols used in the Internet do not provide any security. Tools to "sniff" passwords off of the network are in common use by malicious hackers. Thus, applications which send an unencrypted password over the network are extremely vulnerable. Worse yet, other client/server applications rely on the client program to be "honest" about the identity of the user who is using it. Other applications rely on the client to restrict its activities to those which it is allowed to do, with no other enforcement by the server.

Some sites attempt to use firewalls to solve their network security problems. Unfortunately, firewalls assume that "the bad guys" are on the outside, which is often a very bad assumption. Most of the really damaging incidents of computer crime are carried out by insiders. Firewalls also have a significant disadvantage in that they restrict how your users can use the Internet. (After all, firewalls are simply a less extreme example of the dictum that there is nothing more secure then a computer which is not connected to the network --- and powered off!) In many places, these restrictions are simply unrealistic and unacceptable.

Kerberos was created by MIT as a solution to these network security problems. The Kerberos protocol uses strong cryptography so that a client can prove its identity to a server (and vice versa) across an insecure network connection. After a client and server has used Kerberos to prove their identity, they can also encrypt all of their communications to assure privacy and data integrity as they go about their business.

Connection Pooling & MYSQL

Connection Pooling - Database
In software engineering, a connection pool is a cache of database connections maintained by the database so that the connections can be reused when the database receives future requests for data. Connection pools are used to enhance the performance of executing commands on a database. Opening and maintaining a database connection for each user, especially requests made to a dynamic database-driven website application, is costly and wastes resources. In connection pooling, after a connection is created, it is placed in the pool and it is used over again so that a new connection does not have to be established. If all the connections are being used, a new connection is made and is added to the pool. Connection pooling also cuts down on the amount of time a user must wait to establish a connection to the database.
Definition and Usage - mysql_pconnect()
The mysql_pconnect() function opens a persistent MySQL connection.
This function returns the connection on success, or FALSE and an error on failure. You can hide the error output by adding an '@' in front of the function name.
mysql_pconnect() is much like mysql_connect(), but with two major differences:
• This function will try to find a connection that's already open, with the same host, username and password. If one is found, this will be returned instead of opening a new connection
• The connection will not be closed when the execution of the script ends (mysql_close() will not close connection opened by mysql_pconnect()). It will stay open for future use

JSON - JavaScript Object Notation

JSON - JavaScript Object Notation

JSON is a lightweight computer data interchange format. It is a text-based, human-readable format for representing simple data structures and associative arrays (called objects).

Server response:

{"books":[{"book":
{
"title":"JavaScript, the Definitive Guide",
"publisher":"O'Reilly",
"author":"David Flanagan",
"cover":"/images/cover_defguide.jpg",
"blurb":"Lorem ipsum dolor sit amet, consectetuer adipiscing elit."
}
},
{"book":
{
"title":"DOM Scripting",
"publisher":"Friends of Ed",
"author":"Jeremy Keith",
"cover":"/images/cover_domscripting.jpg",
"blurb":"Praesent et diam a ligula facilisis venenatis."
}
},
{"book":
{
"title":"DHTML Utopia: Modern Web Design using JavaScript & DOM",
"publisher":"Sitepoint",
"author":"Stuart Langridge",
"cover":"/images/cover_utopia.jpg",
"blurb":"Lorem ipsum dolor sit amet, consectetuer adipiscing elit."
}
}
]
}





JAVA SCRIPT Processing
function setDataJSON(req)
{
var data = eval('(' + req.responseText + ')');
for (var i=0;i < data.books.length;i++)
{
var x = document.createElement('div');
x.className = 'book';
var y = document.createElement('h3');
y.appendChild(document.createTextNode(data.books[i].book.title));
x.appendChild(y);
var z = document.createElement('p');
z.className = 'moreInfo';
z.appendChild(document.createTextNode('By ' + data.books[i].book.author + ', ' + data.books[i].book.publisher));
x.appendChild(z);
var a = document.createElement('img');
a.src = data.books[i].book.cover;
x.appendChild(a);
var b = document.createElement('p');
b.appendChild(document.createTextNode(data.books[i].book.blurb));
x.appendChild(b);
document.getElementById('writeroot').appendChild(x);
}
}


PHP JSON
string json_encode ( mixed $value [, int $options= 0 ] )
Returns a string containing the JSON representation of value .