A secure communication link is established between a smart card and a remote central computer system through a network by using security functions at the smart card and the central computer system. A smart card communication device facilitates the exchange of data between the smart card and a local processor by modulating data signals sent from the local processor and demodulating signal transmitted from the smart card. The local processor couples the data signals to the network while maintaining the secure data in its secure state. The secure link can be used to perform a smart card transaction.