Mar 06, 2014 Since Microsoft no longer supports Halo: Combat Evolved for PC I can say this Is legal. However it should only be used if you OWN the game! This CD Key generator project hasn't even begun. Pro reverse engineers will be needed.
My brother is really into Halo right now, and he just got a new PC, so I decided to challenge him to a game of Halo PC. Unfortunately, I was not aware that even in LAN games, CD keys must be unique. However I really wanted to play, so I persevered and was eventually rewarded.
I have decided to document this process, since it does not involve pirating Halo or using any CD keys but the legal one which you possess. /ansible-user-module-generatesshkey.html.
Of course, before you can bypass the duplicate CD key, you need to bypass the CD check. The method I used was to download a special CD image of the Halo PC CD which has the correct file sizes and directory structure, but there is no data in the actual files (ie it's not a pirated copy). It's a nice 800kb size, much better than keeping the full CD image around, and it works. You may also try copying the actual CD, or ripping a CD image and mounting it in Daemon Tools or a similar tool. Of course one of the computers can use the actual CD if you want.
You can and should install Halo PC with the same CD key on all computers, and be sure to run haloupdate.exe to ensure you have the most recent version on all computers.
Run the Registry Editor (regedit.exe from the Run dialog) and navigate to HKEY_LOCAL_MACHINESOFTWAREMicrosoftMicrosoft GamesHalo. You will see a value called DigitalProductID. This contains a bunch of information, including your encoded CD Key (some people say 'encrypted', but it can be easily recovered with one of severaltools, which isn't a useful feature of encryption..) and your support ID. Note that the second link I provided to a tool gives you the offset of the key in the data.. 0x34 to 0x42.
We are going to modify that value, so you will want to export the 'Halo' registry key using the File menu to some place on your disk, so you can easily double click the file to restore your DigitalProductID (which I recommend you do if you want to play online games again.. I'm not sure but when playing online a modified DigitalProductID will probably be detected and rejected as an invalid CD key. Don't ask me why it works in LAN games..). So, all I needed to do was increase the value of the last byte (at 0x42) by one.
Make this a unique value on every computer (of course one won't need to be changed, in my case it was the host, since the real CD Key can still be used once) and they should all be able to join. Note that I only tested this with a server and a client but it should theoretically work with many. Of course, it COULD possibly be a fluke that it worked for me.
If this method does not work for you, go back and make sure you followed every step right. If you're also trying out a no-CD solution for the first time, make sure you can play normal online games (restore your DigitalProductID first!) so you know it's working properly. If you still can't get it to work and you're satisfied you followed the above instructions, drop me a line and let me know (like I said, it's possible it only worked for me by sheer random luck, I haven't exactly done extensive tests).
Launch Halo with the -window parameter from a command prompt to run it in a window instead of full screen. Changing the resolution in-game will change the size of the window. Note that this isn't available as a normal in-game option because it's slightly glitchy (other windows, such as the taskbar, will react to the invisible mouse cursor and may cause the game to slow down). Example: I keep my taskbar on the left with autohide. Whenever I look far enough to the left in Halo, it will pop up as if I've moved the mouse over it. You may want to minimize all other windows and un-autohide the taskbar while you play Halo in a window.
Happy LANning!