## 1 Introduction  
A topic that is currently being frequently discussed is how the electrical power networks will be designed in the future. Nowadays, many application fields have rapidly grown in their technological evolution, including power systems. With the benefits of IEDs and communication networks, the FA system in DNs can easily be applicable. Therefore, the electrical distribution grid recently witnesseda transition from the old-style electrical grid to the new style of grid that is called the SG [1]. By implementing intelligent monitoring and control from a distance to power the equipment, an SG will become a promising platform for increasing the efficiency and the quality of service [2]. The primary purpose of the SG is to combine valuable data from the electrical grid to permit the CC to evaluate the present status of the electrical grid [3]. The objective of SGs is to create a new power grid that runs economically and smartly [4]. In an SG environment, feeder handling can be implemented via automatic reconfiguration to improve the voltage profile, power quality and to reduce the branch power loss [5; 6]. The ability to self-heal, in case of a fault, is one of the required features for a SG, which brings significant economic benefits [7]. The effect of a prolonged outage in the electric DN to an area would be greater than the economic loss. To achieve a fast power restoration, the power utilities have been using smart remote-controlled breakers in distribution networks to ensure continuous power supply. Guaranteeing the continuity of provided power is one of the primary functions of a power system [8]. SG systems with remote and fast switching breakers make network reconfigurations possible and thus, they reduce the breakout period when an outage occurs [9; 10]. The SB can offer new functions such as a real-time remote switch by the CC. The remote signal can be sent by the CC to the SB to connect or disconnect a power line. These breakers have a high impact [11] and become economically sustainable due to a lot of automation equipment and to new communication technologies. The general purpose of computing and communication in power system resources is to improve the system efficiency [12; 13]. In the SG, the SB device lies far from CC and uses two-way communications at normal and fault conditions. Therefore, the maneuvers for self-reconfiguration must be passed in a secure way or through a secure process. The data can be sent to the CC and to the SB over wireless or wired networks. Wireless technologies are extensively used for local communication subsystems in the SG [14]. The wireless communication technology may produce new and important challenges for the security of existing network [15]. For instance, a faked fault data can be invented and forwarded to CC or SB. Therefore, without suitable security, the SG cannot perform well as an energy management system [16; 17]. In this paper, a secure authentication scheme using a new fast technique for a SB in the SG has been introduced. The proposed scheme consists of two scenarios for authentication between the SB and the CC. The first permits a CC to authenticate with the SB, while the second is similar to the first and allows the SBs to authenticate with its CC. Where, the CC or SB will be Sending End (SE), while the SB or CC will be Receiving End (RE). This scheme permits authentication between the SE and the RE. The SE creates a random number, which is then hidden in the breaker ID, to encrypt the result using the hidden parameter. Afterwards, the SE creates the hash value for the proposed authentication and authorization. At last, the RE receives an authentication signal that contains the hash value from the SE. After receiving the authentication message, firstly, the RE re-decrypts the information to get the random number and then it generates a new parameter called the obtained hash value. The obtained hash is compared with the hash that was previously sent from the SE; if both are equal, then the calculated random number was right.