Abstract: A method of delivering a digital receipt relating to a transaction to a user, the method comprising, at a server: receiving transaction related data from a point of sale system, the transaction related data having been intercepted in a data communications path between a point of sale terminal and a peripheral device; analysing transaction related data to extract user identification data; querying a user data module using extracted user identification data to determine user preferences relating to delivery of digital receipts; generating the digital receipt in dependence on the determined user preferences and the received transaction related data; outputting the digital receipt.

Abstract: A computer implemented search method, to be implemented on a computing device, for identifying a user from a first data store, the first data store comprising a plurality of data records, each data record comprising an identifier proxy category for an identifier proxy data item and an associated user identifier category for a user identifier data item, the method comprising: receiving a set of data items relating to a user interaction, the set of data items comprising an identifier proxy data item; formulating an identifier search query comprising the received identifier proxy data item and sending the identifier search query to the first data store containing the plurality of data records; receiving search results from the first data store in the form of one or more data records in which the identifier proxy data item within each returned search result matches the identifier proxy data item in the search query; outputting a user identifier data item from the returned search results.

Abstract: A method of establishing a user profile on a server computer, the user profile being associated with a unique user identifier used during a transaction made by a user, the method comprising: receiving user-related data comprising identification data associated with the unique user identifier; sending a server authentication message to the user in dependence on the user related data; receiving a registration message from the user, the message comprising the authentication message; establishing the user profile in response to receiving the registration message

Abstract: A transaction computing device for interacting with a POS system, the POS system comprising a POS terminal having a software module for processing transactions within a transaction environment and a physical device in communication with the POS terminal, the transaction computing device comprising: an input for receiving transaction data from the physical device; a processor arranged to process the received transaction data to generate modified transaction data; an output arranged to send the modified transaction data to the POS terminal wherein the processor is arranged to: determine whether the received transaction data is associated with a unique identifier and, in response to determining the presence of an associated unique identifier, determine the state of the unique identifier; in response to the unique identifier being valid, retrieve a modified identifier, the modified identifier being in a format compatible with the POS terminal; generate modified transaction data, the modified transaction data comp