PianoPete88 wrote:
Now after upgrading to Yosemite anyone can access my computer because I can't create a secure network!
Not true. Others might see your open connection but in order to access your files on your Mac - and only if you have enabled a File sharing on your Mac - others will need to know your user name and password. In order to access your iTunes Library - if you do use Home Sharing - they will need to know your AppleID and password.
If you do share your iTunes Library via iTunes > File > Preferences > Sharing, then you can add a password to secure your Library.
In other words, no need to panic...
PianoPete88 wrote:

I see nothing labeled 'Source port'. Do you mean the pulldown menu that says 'Share your connection from'?
On that pulldown menu that says Share your connection from changed to Ethernet or anything else that is not WiFi. After that, you should see WiFi option appearing under To computer using: section - if you then enable WiFi on that list, you will see another button appearing on this window called WiFi options... which will give you an option to enable secure network.
PianoPete88 wrote:
Remember I will have no connection to the internet at my shows.
If above will work Internet connection might not be required as your goal is only to setup secure Network connection between 2 devices and if your iPhone will be able to see and connect to your Mac's network then that is all what you need...
I did not have chance to test this so I can't tell if this will work for sure however I would suggest to test this setup at home first before you will hit the stage... 😉