experienced - 5:38 am on Feb 19, 2012 (gmt 0)

i have created a cms for one of my customer with the condition that we will not handover the source file. it is a big time taken software and cost us appx 50000$. can you please advise how to do this so he can not actually make another copy of the software and can install this to only assigned number of domains..

what software i ca use to do this..?