Security for contactless transactions

A method at a terminal of performing a contactless transaction with a payment device, the method comprising:

• establishing a data connection with the payment device;
• establishing if the payment device and the terminal both support an enhanced security architecture;
• and
• if not, performing the contactless transaction according to a basic transaction flow using a first cryptographic system;
• but
• if so, performing the contactless transaction according to an enhanced transaction flow using a second cryptographic system;
• wherein the first cryptographic system and the second cryptographic system comprise different asymmetric cryptographic systems.

A payment device adapted to perform a contactless transaction with a terminal, wherein the payment device is adapted to:

• establish a data connection with the terminal;
• establish if the payment device and the terminal both support an enhanced security architecture;
• and
• if not, to perform the contactless transaction according to a basic transaction flow using a first cryptographic system;
• but
• if so, to perform the contactless transaction according to an enhanced transaction flow using a second cryptographic system;
• wherein the first cryptographic system and the second cryptographic system comprise different asymmetric cryptographic systems.