APP FOR BLOCKING PORN. No bids from indiapakistan

i need an app made for child protection. This app is expected to intercept inappropriate words and then block the content. You can use any method you like , as long as no rooting is required and as long as we do not use an external computer or server, everything must be on that one phone. You will be expected to make your own UI, which should look nice. Budget $300. ABSOLUTELY NO BIDS FROM INDIAPAKISTAN OR INDIAPAKISTAN TRAINED PROGRAMMERS PLEASE. Your bids are final , no price haggling after submitting a bid. My budget is $300, not flexible.