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PHP - protecting code
I have build a php "management" site for a client with some specific features very usefull for their kind of business. So I decided with the client to sell to other companies this back-office software.
How can I close this php site so that clients ho buy it can install it only once and validate it with a key? also, can they just copy all files and db and give it to someone else?
What are the techniques to close a php site as a SaaS?