| 摘要 |
The invention relates to tickets on smart cards. According to the invention, tickets (20) comprise several fields: an entitlement field (21), a validation field (22), and preferably also a verification field (23). Data may be written into the said fields (21, 22, 23) in a protected manner using a different key (K1, K2, K3) for each type of field. A further protection of the integrity of the tickets is obtained by using a first storage command (UPDATE) to prepare a field when issuing the ticket and using a different, second storage command (WRITE) when validating the ticket. Preferably, in the tickets a code is used having a fixed number of set bits, thus preventing the fraudulent modification of an issued ticket. <IMAGE> |
