Patent ID: 8571995

Claim:
A computer-implemented method for securing payment card data in a system having at least one point of sale terminal and at least one payment card transaction processing gateway, the method comprising: deriving, by a key server, an intermediate key from a master key; sending, by the key server, the intermediate key to the at least one payment card transaction processing gateway; deriving, by the key server, a first terminal key from the intermediate key; sending, by the key server, the first terminal key to the at least one point of sale terminal; obtaining, by the at least one point of sale terminal, payment card data associated with a payment card of a user during a purchase transaction; encrypting, by the at least one point of sale terminal, the payment card data using an encryption algorithm that takes as inputs a first part of the payment card data, a tweak formed from a second part of the payment card data, and the first terminal key; transmitting, by the at least point of sale terminal, the encrypted payment card data and the tweak, to the at least one payment card transaction processing gateway; deriving, by the at least one payment card transaction processing gateway, a second terminal key from the intermediate key; and decrypting, by the at least one payment card transaction processing gateway, the encrypted payment card data using the second terminal key and the tweak.