Patent ID: 8433914

Claim:
A method performed in a first client-side device, the method comprising: receiving transaction data, at the first client-side device, over a first communication channel from a remote server, in response to a user submitting a transaction request to the remote server via a second client-side device, the second client-side device being distinct from the first client-side device, over a second communication channel, the second communication channel being distinct from the first communication channel; displaying the received transaction data in a format visible to the user; receiving, at the first client-side device, confirmation from the user that the displayed transaction data is correct; receiving, at the first client-side device, additional transaction data from the user, the additional transaction data including information concerning the transaction request not included within the received transaction data; in response to receiving the confirmation from the user, calculating, at the first client-side device, a cryptographic signature based on the received transaction data and a cryptographic key; and delivering the cryptographic signature to another entity for authentication, wherein delivering includes: sending the calculated cryptographic signature from the first client-side device to the remote server over the first communication channel; wherein calculating includes calculating the cryptographic signature based on the received transaction data, the additional transaction data, and the cryptographic key.