The game server generates a winning combination of the future game, encrypts it by an unidirectional hash function with a Crypto-Key into an Open Code and transmits the Open Code to the app in a E-ticket.
Therefore, before entering the game, the player gets a unique encrypted information with the game winnning combination and the game operator may rightly declare:
“Every E-ticket carries the Main Prize”.
When the game ends, the game server transmits to the app a E-coupon containing prize data, the Open Code and a Secret Code with server’s Crypto-Key and the winning combination of the game. E-coupon includes also a QR-coded link to a public web-site to check up byte-by-byte the Fair Play Criterion:
Hash(Secret_Code) - Open_Code = 0.