(en) MultiPath TCP (MPTCP) is a recent TCP extension that enables hosts to send the data belonging to one connection over multiple paths. It is already deployed for various use cases, notably on smartphones. In parallel with this, there is a growing deployment of encryption and authentication techniques to counter various forms of attacks. Tcpcrypt and the Transport Layer Security (TLS) are some of these security solutions. In this paper, we propose MPTCPsec, a MultiPath TCP extension that closely integrates authentication and encryption inside the protocol and shows how it counters several types of attacks.