| 摘要 |
The invention relates to a method and device for detecting a modification in a signaling message sent from a network unit (MSC/SGSN) to a communications terminal (MS). According to the invention, a bit sequence, which is contained in a sent signaling message (authentication request) and which is known to a network unit (MSC/SGSN) and to the communications terminal (MS), informs the communications terminal (MS) that a test value is contained in a signaling message (authentication request; additional message). In addition, the test value received by the communications terminal (MS) is compared with a test value computed by the communications terminal (MS), and the communications terminal (MS) defines a signaling message (authentication request; additional message) as being unmodified only in the event that the bit sequence contained in a signaling message (authentication request) has been received and the comparison of both test values yields a positive result. |
