Abstract: A method is provided which comprises receiving at a server system associated with a card issuer or card program manager a transaction request for a transaction, the transaction request containing data to identify a customer account number; determining a mobile computing device associated with the customer account number; transmitting to the mobile computing device a payment request, the payment request comprising: (i) a requesting entity certificate signed with a private key of the card issuer or card program manager, and (ii) transaction data specifying the transaction and signed with the private key defined in (i); and receiving from the mobile computing device a payment authorisation message to authorise the transaction, the payment authorisation message comprising a cryptogram based on (i) data contained in the requesting entity certificate, (ii) data contained in a payment entity certificate, (iii) transaction data and (iv) mobile computing device data, where the cryptogram is signed with a cryptographic

Abstract: A client system obtains data content or is linked to data processing systems related to user selected data content within a portable document file. The client system comprises a browser system for receiving an HTTP package containing a first portable document file, the first portable document file comprising display class data content selectable by the user and related hidden class data content. The client system further comprises a display module for displaying the display class data content on a display screen associated with the client system. The client system further comprises a message module for building a message in response to user selection of display class data content, sending the message to a message server, and receiving a second HTTP package containing a portable document file from the message server.

Abstract: A message server comprises web server systems for sending a first portable document file to a client system. The first portable document file comprises displayed data content selectable by the user and associated hidden data content. The hidden data content may be in a tagged data content format. The message server receives a message from the client system. The message comprises both: i) identification of the first portable document file; and ii) identification of the displayed data content selected by the user. The message sever uses the identification of the first portable document file and the identification of the displayed data content selected by the user to link the client system to a data processing system at a specified network address, the data processing system being related to the content selected by the user.

Abstract: A message server comprises web server systems for sending a first portable document file to a client system. The first portable document file comprises displayed data content selectable by the user and associated hidden data content. The hidden data content may be in a tagged data content format. The message server receives a message from the client system. The message comprises both: i) identification of the first portable document file; and ii) identification of the displayed data content selected by the user. The message sever uses the identification of the first portable document file and the identification of the displayed data content selected by the user to locate and provide a second portable document file that is related to the content selected by the user.