Who Made Scratch off Lottery?

Beginning: According to New York Times Article,In 1960, Grocery stores handed out free cards covered with a waxy coating that hid a cash prize, which was a small amount , such as half-penny. They would printed 200 different tickets only few of which would be winners. 

Problem with Ticket: those free cards with winning prizes were easy to find the winning tickets because there was special design, a stray mark or a serial number  

Solution: 

 In '70s, two Card company workers named John Koze and Dan Bower came up with idea to make this free cards (Lottery) into money making tool. They printed about 20000 lottery tickets with so many different patterns which makes impossible to identify the winning one. They Flew to Boston and meet with Massachusetts lottery officials and promoted their system as secure and impossible to crack

                       

Source: Who Made that Scratch Off Lottery Ticket <http://www.nytimes.com/2013/07/07/magazine/who-made-that-scratch-off-lottery-ticket.html>