Cryptography Network Security Lecture Notes Pdf
Video lecture on computer security, protection, security goals, the safety net approach, and cryptography.
• Just one brief announcement. HKN reviews are going to be done in class next Monday so you guys should make sure you come, give us your feedback, let us know what you like and what you don't like. And, with that, we'll start talking about protection. Protection is like fault-tolerance and recoverability. One of these properties of systems, or building secure and protected systems has implications for the entire design of the system. And it's going to be sort of a set of cross-cutting issues that is going to affect the way that, for example, the networking protocols are designed or that the sort of modules that make up your biggest computer system are designs. So it's going to be a whole set of usually that we're going to look at through the course of this discussion about protection that are going to affect the system at all levels.
In 6.033, we use the work protection and security essentially synonymous. Often times we'll talk about a secure system or a system that has security or certain security goals that we have, so we're going to use those words interchangeably.
Security is one of these topicals that you guys are familiar with to some extent already. You've heard about various things on the Internet going on where people's information has been stolen on laptops or a website has been cracked into or some worm or new virus, the new I love you virus is spreading around and confection people's computers. So you guys are sort of familiar with it on a collegial sort of way, I'm sure. You also are familiar with many of the tools that we're going to talk about, so the applied versions of the many of the tools that we're going to talk about. You've all used a password to lock into a computer before or you've used a website that using SSL to encrypt the communication with some other website.
So you're going to be familiar with some of many of the high letter instances of the tools that we'll talk through in this session, but what we're going to try to delve down into in 6.033 is how those systems are actually put together, what the design principals are behind building these secure systems. As I said, you guys are presumably very familiar with, you've heard about these various kinds of attacks that are going on. And one of the things that's happened in the last few years, as the Internet has become more and more commercial and larger and larger, is that it's meant that security of computers has become much, much more of a problem. So the growth of the Internet has spawned additional attacks. If you go look at a website, for example, there are several security websites that track recent security breaches This is one example. It's called Security Focus dot com. I don't know if you can see these, but this is just a list of things that have happened in the last just few days on the Internet.
Somebody is reporting that web server hacks are up by one-third, some IT conference was hacked, Windows says 'trusted Windows' is still coming. [LAUGHTER] So it just goes on and on with these are things that have happened in the last few days. There is this huge number of things. Font Helvetica Neue Ots Download Skype. You may have heard recently about how there have been several large companies recently that have had big privacy problems where databases of customer information have been stolen.
AmeriTrade just had this happen. The University of California at Berkeley had something like several hundred thousand applications and graduate student records were on a laptop that was stolen.
These are the kinds of things, the kinds of attacks that happen in the world, and these are the kinds of things that we're going to talk about how you mitigate. The objective, really, of security, one simple way to look at an objective of security is that we want to sort of protect our computer from bad guys. The definition of bad guy depends on what you mean.
It could be the 16 year old kid in his dorm room hacking into people's computers. It could be somebody out to sleep hundreds of thousands of dollars from a corporation, but let's assume that there are some bad people out there who want to sort of take over your computer. But, at the same time, the objective of security is also to allow access to the good guys. So one way to make sure that the bad guys don't get at your data is simply to turn your computer off, right? But that's not really a good option.
We want the data to be available to the people who need the data and have the rights to access the data. Often times we can sort of frame our discussion, we can say that we're trying to protect we have some set of information that we want to keep private. So sort of a goal of a secure system, in some sense, is providing privacy. So we have some set of data that's on our computer system or that's being transmitted over the network that we want to keep private, we want to keep other people from being able to have access to or tamper with. And throughout the sort of notion of what it means for a computer system to be secure is sort of application dependent. It depends very much on what the computer system we're talking about is.