Ok, I have no idea where to start with this...

THIS IS HOMEWORK - So please don't give me the answer just guidance. Thank you!

Question:
You are building a large-scale application that will be compiled onto a CD and installed and run on a client's computers. You need to create serial numbers for each CD, but each CD has to work with only the serial number that it has been given and if it detects another serial number being used shut down the program.

You can't have any 2 numbers so closely related that if someone makes a typo it shuts down the CD. You are trying to weed out the duplicated serial numbers from getting to use the application.

Justin:
So basically I have to build this application that generates random serial numbers for each CD.. Ok random numbers sounds good. Then I have to ensure that each CD has a different serial number. Only way I can think of is to create a database on the net and have each CD check the serial numbers through the net... I wouldn't want to include the datbase with the program as all a person would have to do is check the serial number I would guess... So that's where I am lost... anyone have any guidance or wisdom?

What if the person installing the program doesn't have an internet-connection (I take it that's the reason why the company wants the program on a cd)?

OK, to check there is only one instance of a program running at once couldn't you create a persistent connection with an online server? If two people connect with the same code shut one of them down. This is how it work's on video games.

As for the keys. I would assume you could use a complex algorithm to generate cd keys. You could then include a decryption algorithm on the CD. Assuming the CD is compiled and not made from a scripting language the decryption algorithm should be safe enough. This is how I assume basic CD encryption works.

Who doesn't have an internet connection? Even the tribes fairing the jungles of Africa have internet don't they? haha.. Good point... Cause what if the internet goes down how will they connect... I'm guessing I'm going to have to program an "If the internet is not available" Make them call and give them a secret activation code... Maybe that will be a good way around it.

I hate when we get complicated problems like this... cause it makes me think... and I thought I was over thinking 2 semesters ago... lol.

Jason, yeah I could do that, but if their internet goes down they won't be able to use the program at all... That's one of the problems that happens with games too. We usually program in Java or (C++, C#, or VB.Net) depending on what the professor asks... I have to turn in a report before I program this so I have a while to figure it out just wanted to see if anyone on here had any good suggestions.

Thanks for the information both of you are helping me think of a solution.

HAHA!!! Mark has an excellent point. Something that certain field officers at work must deal with They have laptops but no internet connections. It's been working that way for over 10 years and just now they are looking at adding wireless connections on those laptops. However, due to the important/valuable/secretive nature of the data they collect, they are having major problems finding a bullet-proof solution.

Just something you might want to think about. NEVER assume someone has an internet connection for a desktop app.

Well yall should see my professor... He's only a few years older than I am and he ticks me off soooo much.. He can write a fully functional banking application in Java with security features in about 30 minutes... AND it is incredible... He's sooo good and so fast it just makes me jealous.. lol I was working on a banking application in Java all semester and I was asking my professor for help. He said "I haven't even done it yet to be honest, hang on let me go do it now". He writes the entire thing in class and then shows me where I went wrong... took me a whole semester to do what he did in a 1/2 hour. Of course it wasn't something with bells and whistles but it was amazing watching that guy work. He told me that 5 years ago it would have taken him all semester too so not to worry, haha.

I think that you said number serial, why not add letters, that way the chance of having typos the same drops

Here's an idea...

1. Generate a unique random serial number
2. Use one-way encryption to encrypt the generated serial number
3. Save the encrypted serial number in a file on the disc

Then, when the user types in the the serial number...

1. Use the same encryption above to encrypt the user input
2. Compare the encrypted user input with the encrypted serial number saved on the cd

If they match, let them use the cd. If not, shut it down.

Hope this helps!
Rich

Does anyone know if Rewake is human? I don't see how he can be... cause he seems to have a knowledge base beyond comprehension... And just to make sure.. your not my professor are ya? lol. Dang man Encryption on the CD, I hadn't even thought about before... What an awesome idea. That'd add security without the need of a database... and even better it cuts out the need for a internet connection.

Now I have to learn how to do this encryption... Thanks so much for all the replies guys!