## 2 Related Works
### Traditional Security Protocols for Wireless M2M and IoT Communications  
Many protocols have been proposed to secure communications between sensors, actuators and other devices for M2M device networks. Identity and authentication management of the interconnected devices can be maintained by a central authority founded on the Public Key Infrastructure (PKI). Unfortunately, methods based on IP-Sec, and SSL/TLS are inadequate for resource-constrained devices with limited computational resources. Other studies [9; 10] have focused on 6 LoWPAN (IPv6 Low Power Wireless Personal Area Network) developed by IETF Internet Engineering Task Force in RFC 6568. SPINS [11] is considered as the first security protocol that addresses various wireless security requirements, primarily at the device level. To encrypt messages and to generate message authentication codes, SPINS uses a lightweight version of RC5. It ensures security services separately over two protocols for unicast and multicast communications; however SPINS presents the forwarding problem. TinySec [12], and Minisec [13] are authentication protocols operating, respectively, at link layer and network layer. They are considered as efficient authentication protocols, particularly well adapted for constrained nodes. Tinysec is the first fully implemented security protocol for WSNs, based on the message authentication code (MAC) and Cipher Block Chaining (CBC). Its drawback is related to the use of a single key to generate MAC codes. Lightweight authentication and key distribution (LAKD) protocol for M2M communications is proposed in [7]. It permits a device to be sure of the identity of any other device before communication takes place. LAKD generates and distributes keys to be used to provide security services (confidentiality and integrity of exchanged data). Using basic operations that not require high processing resources (xor, addition, subtraction, etc. ), LAKD is considered as an adequate protocol for devices with very limited resources. In [8], the authors present lightweight authentication mechanism, based on hash and XOR operations, for M2M communications between a resource constrained industrial device (e.g., a smart sensor) comprising a secure element (SE) and a router comprising a TPM (Trusted Platform Module). In [9], the authors propose a mutual authentication and key establishment for M2M communication in 6 LoWPAN Networks. The protocol applies ECDH (Elliptic-curve Diffie-Hellman) algorithm to implement the secret key distribution among nodes. Based on the analysis of EAKES6 Lo protocol, showing its defect due to data loss after node capture, and its vulnerability to sinkhole attacks and plaintext chosen attacks, a new M2M communication mutual authentication protocol based on 6 LoWPAN is proposed in [10]. The protocol builds up a sensible secret key dissemination mechanism and plans an anti-capture attack detection strategy for unattended nodes to stand up to attacks such replay attacks, sinkhole attacks, plaintext-chosen attacks, and physical capture attacks. SAKES (Secure Authentication and Key Establishment Scheme) is proposed in [14]. It is based on lightweight public-key cryptography using ECC scheme in order to establish the session key. This one is established between the 6 LoWPAN and the server, based on Diffie Hellman exchange. To decrease the computational load, related to cryptographic operation, on the sensor nodes, SAKES executes the computations on the gateway nodes and sends computed keys to the sensor nodes through the 6 LoWPAN context. Paper [15] proposes a three-factor authentication framework based upon a publish-subscribe pattern using message queue telemetry transport (MQTT) as application communication protocol. The general architecture supports mutual entity authentication between a remote user (subscriber), broker (gateway), and IoT node (publisher), based on password, identity and low-cost digital signature, using elliptical curve cryptography.