Software Engineering Institute

French smart cards are credit cards with an embedded chip containing certain cardholder, account, and authentication information. These cards are read by automated terminals across France for sale of a variety of products and services.

Prior to November 1999, authentication was performed on the terminals by reading a 320-bit RSA-encrypted authentication value from card, decrypting the value, and comparing it to the unencrypted account information stored on the card. The encryption method used a 321-bit RSA key which was cracked in or before 1998 and published on the Internet on February 9, 2000. With knowledge of the key now public, criminals have begun to forge their own credit cards with valid authentication values on bogus accounts. Because the terminals check only the information stored on the card without verifying the account validity with the credit card issuer, the terminals are fooled into accepting the card and dispensing product or providing services.

Starting in November 1999, new smart cards contained a second authentication value of 768 bits. However, with 37 million of the old cards already in service, most terminals were either not upgraded to use the new authentication scheme or were upgraded with backward compatibility enabled for the older cards.

Attackers can forge smart cards that will be accepted as payment at over two million estimated automated card reader terminals in France.

Merchants should upgrade their smart card reader terminals to require the new authentication scheme introduced in November 1999. Cardholders of cards issued before November 1999 should obtain new cards.