Abstract: A method of validating a merchant in a point of sale transaction system, comprising the steps of encrypting a customer secret identification information using a public key of the merchant, entering the encrypted information into a transaction device, transmitting the encrypted information from the device to a merchant, decrypting at the merchant and the encrypted secret identification information, and transmitting the decrypted secret identification information from the merchant to the device wherein the customer verifies the decrypted secret identification information by visual inspection of the secret identification information.

Abstract: A data processing method for handling of errors in communication between a wireless device and a server in a wireless transaction processing system, the method comprising the steps of creating, within persistent storage, a transaction log containing recovery information which can be used for recovery from errors in communication during a transaction; determining whether error correction information received from said wireless meets at least one predetermined criterion; and performing an error handling process if the received error correction information meets the predetermined criterion.

Abstract: A method for unifying payment transactions between a customer and a merchant, the transactions using customer information stored in one or more electronic wallets, the method comprising the steps of; Providing to the merchant an entity having a unifying interface to the one or more electronic wallets, the entity communicating with both the one or more electronic wallets and the merchant; and the entity collecting customer information from the one or more electronic wallets and payment transaction details from the merchant and processing the transaction in a financial institution.