help:how to give subdomains for free securely?

hi. i have a deluxe plan linux server from godaddy, with 100000mb of space, and 1tb of bandwith, so ive decided to give subdomains to some of my users, i also hava unlimited ftp accounts,
is there a secure way to do this? the only thing i care is that they can enter of someway to the root domain...
and if theres a software, script or something that does this automatic, it will be better.

thanks.

edit: more info, i got unlimited subdomains, but they have to be in a folder, example dogs.xxx.com files goes on www.xxx/dogs

 

I dont know how godaddy panel works. But I believe you can set a password for this subdomain, plus you limit the ftp account to strictly that subdomain/folder.

However, You will have to monitor the content of the subdomains to ensure you dont violate godaddy TOS without knowing it.