Android and ios app

Hi, i need the realization of an app (ios and android) that read the bar code and qr code and make validation. We will award the most quickly developpers that guarantee us very faster scan library, to be used trought cam of mobile device. The payment policy is this: we will escrow step by step while the app is in progress, till to arrive to the agreed total. Just at the end and only when all is done and you send the sources code and we have checked it, we will release the escrow. PLEASE DON ASK IN ADVANCE TO RELEASE escrow or part of it. IF YOU DONT AGREE WITH THIS METHOD OF PAYMENT DONT BID. More details in private message