Abstract: A secure payment system comprises a merchant POS client and a remote POS server. The merchant POS client comprises a reading device for reading a customer user token and for accepting transaction details and customer verification data, and also a computing device with access to a communications network and in communication with the reading device. The merchant POS client also comprises a merchant token associated with the remote POS server. The remote POS server is in communication with the merchant POS client through the communications network, and one or more elements of the merchant POS client business logic are assured by the remote POS server and not the merchant POS client. A merchant token for use in such a merchant POS client is described, as is a suitable reader device, and a method of conducting a transaction using such a payment system.

Abstract: A credit account is established for a merchant. A variable credit limit is set for the credit account. An indication is received that the merchant has accepted a payment account transaction to be charged to a customer's payment account. A transaction amount may be associated with the payment account transaction. The indication may also indicate that the payment account transaction has been authorized by an issuer of the customer's payment account. There may be a response in real time to the indication by instantaneously increasing the variable credit limit for the merchant's credit account by an amount that corresponds to the transaction amount.

Abstract: Methods and systems for facilitating operation of mobile devices as either consumer payment devices and/or merchant payment devices for completing purchase transactions. A process includes a consumer mobile device initializing a two-sided payment application, receiving a handshake indication at a merchant location from a merchant device running a copy of the two-sided payment application, and establishing a communications path between the consumer mobile device and the merchant device via a remote network connection. Purchase transaction detail data is then exchanged, the purchase transaction detail data is transmitted to a mobile gateway computer for authorization processing, and both the mobile device processor and the merchant device processor receive an authorization message to consummate the purchase transaction.

Abstract: A secure payment system comprises a merchant POS client and a remote POS server. The merchant POS client comprises a reading device for reading a customer user token and for accepting transaction details and customer verification data, and also a computing device with access to a communications network and in communication with the reading device. The merchant POS client also comprises a merchant token associated with the remote POS server. The remote POS server is in communication with the merchant POS client through the communications network, and one or more elements of the merchant POS client business logic are assured by the remote POS server and not the merchant POS client. A merchant token for use in such a merchant POS client is described, as is a suitable reader device, and a method of conducting a transaction using such a payment system.