Payment system

An electronic transaction payment system comprising:

• a user terminal;
• a first smart-card associated with a first user;
• a first smart-card reader for transmitting data to and receiving data from said first smart-card;
• a second smart-card associated with a second user;
• a second smart-card reader for transmitting data to and receiving data from said second smart-card;
• a registry terminal comprising an interface to interface with said user terminal;
• wherein said user terminal is configured:
• i) to interface with the smart-card reader of the smart-card associated with the user that will make a payment;
• and
• ii) to transmit transfer data identifying a payment to be transferred between the first and second users, to a smart-card associated with the user that will make the payment via an associated smart-card reader;
• wherein said first smart-card is configured to output a request for data describing the second user, for transmission to said registry terminal;
• wherein said user terminal is configured to receive the request for data describing the second user output from the first smart-card and to transmit the request to said registry terminal;
• wherein said registry terminal is operable to receive the request for data describing the second user from the user terminal and is operable to transmit data describing the second user, in accordance with the request, to the user terminal;
• wherein said user terminal is operable to receive the data describing the second user from the registry terminal and to forward the received data to the first smart-card;
• wherein the first smart-card is configured to receive said data describing the second user from said user terminal, to determine whether or not said data describing the second user conforms to a predetermined condition;
• and, in response to said determination, to control whether or not a payment is to be made between said first and second users;
• wherein the smart-card associated with the user that will make the payment is configured:
• i) to receive said transfer data indicative of the payment to be transferred;
• ii) to encrypt payment data to be transmitted to a smart-card associated with the user that will receive the payment;
• and
• iii) to output the encrypted payment data for transmission to a smart-card associated with the user that will receive the payment;
• and
• wherein a smart-card associated with the user that will receive the payment is configured:
• i) to receive said encrypted payment data;
• and
• ii) to decrypt said encrypted payment data to obtain the payment.