The current invention provides a mobile payment method and a number of variations that enable a consumer to pay for a purchase from a merchant. Preferably the consumer may use a mobile device such as a smart phone to complete the transaction. With the current invention, the merchant may be capable of conducting the transaction using only an ordinary point of sale (OPOS) terminal, allowing the merchant and consumer to conduct business in a more convenient manner. The variations of the core method also significantly facilitate possible payment from the consumer to the merchant, enhancing the efficiency of the transactions.