SCTP (Stream Control Transmission Protocol) has enhanced data transport performance due to its interesting features such as multihoming and multistreaming. However, nowadays, the requirement for mobility through different wireless networks has been steadily increasing. Hence, the need for vertical handover between heterogeneous networks in the wireless communication environments has led researchers to propose the mobile Stream Control Transmission Protocol (MSCTP) that supports the soft handover for mobile nodes due to the SCTP multi-homing feature and DAR extension. In other hand, these features that facilitate updating the IP address of an SCTP association seamlessly make the handover more vulnerable under several attacks. Therefore, in this paper, we propose an authentication protocol to secure the MSCTP's handover. Our solution is analyzed using SPAN (Security Protocol Animator) for AVISPA (Automated Validation of InternetSecurity Protocols and Applications) tool. The results have shown that the scheme is safe.