Abstract: A method of performing an authorization mechanism between a service terminal system (ATM) and a helpdesk system (HD) includes the steps of: sending a request message (RQ) comprising a one-time code (CL), an identifier (CN) for the ATM and a set of access right data (TD) about rights for using the (ATM) by a user (TN); creating a response message (RS) by using the CL, TD, and an ident key (TK) derived from an operation on the CN and a base key (BK), the BK being a common secret of both, the HD and the ATM; sending the RS; creating a reference response message (RS*) by using the CL, the TD, and the TK; and comparing the RS with the RS* to authorize the TN to use the ATM according to the rights being represented by the TD.

Abstract: A method of performing an authorization mechanism between a service terminal system (ATM) and a helpdesk system (HD) includes the steps of: Sending a request message (RQ) comprising a one-time code (CL), an identifier (CN) for the ATM and a set of access right data (TD) about rights for using the (ATM) by a user (TN); Creating a response message (RS) by using the CL, TD, and an ident key (TK) derived from an operation on the CN and a base key (BK), the BK being a common secret of both, the HD and the ATM; Sending the RS; Creating a reference response message (RS*) by using the CL, the TD, and the TK; and Comparing the RS with the RS* to authorize the TN to use the ATM according to the rights being represented by the TD.