| 摘要 |
<p>The invention provides a method for protectedly debiting an electronic payment means (11), such as a telephone card. In the communication protocol between a payment means (11) and a payment station (12), an authentication is used to identify the payment means during various steps of the protocol. According to the invention, the authentications are mutually related by states (Y1, Q2) of a cryptographic process (F) in order to be capable of detecting an interference in the protocol. The method may be applied to existing payment cards having a dynamic memory, it being guaranteed that the contents of the dynamic memory, in which there is located information related to the authentication, is not lost during the protocol.</p> |
