Requirements

1. registerGame (GameName, GameOwner, LegalAddress, ContactDetails, unitCost, GamePassword)::GameID
2. registerGameUser (GameId, GameUserID, currency)::UserID
3. buyTokens(UserID, numberOfUnits)::returns play4CashSession or error (total amount = numberOfUnits * unitCost + commission)
4. cashOut (play4CashSession, UserID, numberOfUnits)::Paypaol trans OK||NOT OK - Async
5. updateScore (play4CashSession, UserID, newUnits)::play4CashSession
6. listSessions(GameID)::play4CashSession[]

GameID

1. UUID
2. HashedGameID = Hash(GamePassword, GameName, GameOwner, RegistrationTime, Play4CasheSecrectKey4Game)

UserID

1. GameUserID
2. HashedGameID

play4CashSession

1. GameID
2. UserID
3. HashedSessionID - regenerated on every request = Hash (lastRequestTime, SessionSecretKey, HashedGameID, UserID, lastUserUnits)