welcome to information security IV. This is the 4th in the series of the 3 courses that we had offered earlier, the first one basically introduced you to all the notations terminologies of the entire game of information security starting from hardware, architecture, software, compilers and then network etcetera. The second course actually dealt with some of the hardware features that are available for you to build a secure system. The third course introduced you to different face such of operating systems and networking; which are the foundation building blocks for understanding security at these levels. Now in the 4th course we are now going to deal with something which is very important and interesting which is 4 and 6 of information security attacks. What we will be covering is that we will be giving you some case studies of some of the information security attacks that had happened and, but importantly we will cover some of the details; that will make you quite proficient with understanding the system and the networking in detail that will enable you to do 4 and 6 in a logical directed way. Any information security system today needs to be protected and in case of an attack should provide enough information for us to go and trace out what has happened.