Inter national J our nal of Electrical and Computer Engineering (IJECE) V ol. 11, No. 2, April 2021, pp. 1375 1387 ISSN: 2088-8708, DOI: 10.11591/ijece.v11i2.pp1375-1387 r 1375 A trust-based authentication framew ork f or security of WP AN using netw ork slicing Sazia P ar vin 1 , Amjad Gawanmeh 2 , Sitalakshmi V enkatraman 3 , Ali Alwadi 4 , J amal N. Al-Karaki 5 , P aul D . Y oo 6 1,3 Melbourne Polytechnic, V ictoria, Australia 2 Department of Electrical Engineering, Colle ge of Engineering and IT , Uni v ersity of Dubai, Dubai, United Arab Emirates 4 School of Engineering, Auckland Uni v ersity of T echnology Auckland, Ne w Zealand 5 Department of Information Security Engineering T echnology , Ab u Dhabi Polytechnic, Ab u Dhabi, United Arab Emirates 5 Department of Computer Engineering, The Hashemite Uni v ersity , Zarqa-Jordan 6 Department of Computer Science and Information Systems, Birkbeck Colle ge, Uni v ersity of London, London, United Kingdom Article Inf o Article history: Recei v ed Apr 25, 2020 Re vised Aug 7, 2020 Accepted Aug 18, 2020 K eyw ords: Authentication Security Substantiality T rust WP AN ABSTRA CT Ne w technologies and their seamless wireless interconnecti vity bring along man y chal- lenges including security and pri v ac y issues that require immediate attention. W ireless personal area netw orks (WP ANs) are characterized by limited ener gy res ources and computing po wer which call for lightweight security mec hanisms in these netw orks as a mandatory requirement. In this paper , a lightweight trust-based frame w ork for node authentication in WP AN is proposed. Our main obj ecti v e is to minimise the ef fort in distinguishing v alid requests of trustw orth y nodes from in v alid requests of mali- cious nodes that can result in netw ork compromises. W e achie v e this through netw ork slicing whic h di vides the netw ork into primary and secondary virtual net w orks. The proposed frame w ork has three-fold benefits. Firstly , it authenticates nodes’ requests based on a no v el method of trust v alue calculation. Secondly , the frame w ork maintains ener gy ef ficienc y while authenticating nodes’ requests to access WP AN resources. Fi- nally , the frame w ork pro vides a solution for the biasing problem that can arise due to une xpected beha viour of malicious users in WP ANs. The frame w ork ef ficac y is illustrated by using a case study to sho w ho w it can accurately capture trust relations among nodes while pre v enting malicious beha vior . This is an open access article under the CC BY -SA license . Corresponding A uthor: Amjad Ga w anmeh Colle ge of Engineering and IT Uni v ersity of Dubai, Dubai, U AE Email: amjad.g a w anmeh@ud.ac.ae 1. INTR ODUCTION Recent rapid adv ancements in wireless communications, sensor technologies, and the Internet of things (IoT) ha v e resulted in the e v olution of wireless body area netw ork (WB AN) and wireless personal area netw orks (WP AN) into an interdisciplinary netw orking paradigm, connecting people with v arious real-time applications including heal thcare, sports, entertainment and social media [1–5]. WP AN is a v ery common and pre v ailing technology that is used to monitor and collect data from a ph ysical en vironment through sensors that can be attached to the person, implanted, or deplo yed around the person’ s confined area. While a WB AN interconnects independent nodes (e.g. sensors and actuators) that are present in, on, or around a human body , a J ournal homepage: http://ijece .iaescor e .com Evaluation Warning : The document was created with Spire.PDF for Python.
1376 r ISSN: 2088-8708 WP AN is a connected netw ork of de vices centered on an indi vidual’ s personal w orkspace . Due to their inherent limitations in memory and po wer , the y are vulnerable to malicious attacks since current security solutions are not suitable to protect each node as well as dynamic topology of distrib uted data processing in WSN [6, 7]. W eak security in WSN can ha v e an adv erse impact that could e v en result in life-threatening condi- tions in healthcare [6]. In addition, dif ferent types of short range wireless netw orks are constantly e xpanding with v arious de vices attached as demonstrated in [8]. The v arious types of WP ANs applications raises se v- eral issues related to preserving data confidentiality and pri v ac y [9]. W ith the increased use of WP ANs in v arious applications that can impact both personal and professional life, it is important to b uild a lightweight trust-based authentication frame w ork for ensuring their security [10, 11]. W ith this aim, the focus of this research is to propose a security frame w ork to safe guard WP AN with a simplified and lightweight trust man- agement mechanism. Se v eral studies ha v e demonstrated the feasibility of security attacks on these types of netw orks [12], thus, WP AN is considered as a threat by indi viduals due to the e xisting vulnerabilities in pro- tecting their personal data and pri v ac y [13]. T raditional authentication and trust management methods of WP AN are inef fecti v e and the current security situation w arrants an ef ficient lightweight security method with minimum o v erhead. Such a solution must address se v eral security concerns in WP ANs: i) a malicious node in WP AN could ab use its resources with selfish beha vior; ii) a malicious node treated as a primary user could stop secondary nodes from using the netw ork; and iii) malicious nodes could create biased nodes with traditional trust management schemes as their true trust v alues are not kno wn. While trust in WP AN has been discussed in the current state of the art [14], the method applied are not suitable for WP AN. Firstly , most trust-based schemes are applied only for routing problem in WP ANs and not for pre v ention of access to untrustw orth y node. Secondly , due to the dif ficulty in calculating the true trust v alues for biased nodes for authentication in WP AN conte xt, there is paucity of research t o address this problem. Finally , to the best of our kno wledge, no solution for authentication in WP AN using trust management scheme e xists to enhance security in WP ANs using netw ork slicing, where nodes belong to either a primary or a secondary virtual group. Se v eral methods were proposed to address security in wireless application oriented netw orks, includ- ing the w ork reported in [8], which addressed the issue of detecting impersonation attack in wireless W iFi. Recently , time-bound lightweight frame w orks that are services-based in processing security policies are stud- ied [15]. Some security approaches are tool-based and focus on the netw ork routing protocols as well as authentication and encryption techniques [16]. Existing WP AN security methods are predominantly limited in solving a specific problem [17, 13]. Man y ne w models and metrics for trust e v aluation proposed are not generic and consider specific location-bas ed pri v ac y , backw ard broadcasting or tunnelling issues [18, 19]. Such schemes require h ybrid security architectures that use dif ferent algorithms for dif ferent problems. In pre vious w ork, Sazia et al. [20] proposed trust-based authentication mechanism in cogniti v e radio netw orks (CRNs) to secure the spectrum sharing process. Ho we v er , it did not address trust-biasing problem. Subsequently , Sazia et al. [21] proposed a community-based grouping technique to ensure the trust-based authentication pro- cess in CRNs, and in [22] secondary node authentication i n WB AN w as introduced. Ho we v er , it lack ed the proof of trust e v aluation for aut hentication. T rust is important as it is a measure of a node’ s reliability and security within the netw ork throughout its communication with other nodes. Other w orks ha v e limited focus of trust in healthcare applications for quality of data deli v ery and netw ork operations [23]. This paper aims to address the issue of node authentication in WP ANs in general. It propos es a no v el lightweight method t h a t can enhance the security of WP AN taking into consideration the topology and nature of the netw ork paradigm. Existing solutions are resource e xtensi v e while WP AN do not ha v e computational po wer . Further , some nodes or implanted de vices are dif ficult to be maintained with limited po wer supply , and WP ANs ha v e dynamic and mobile characteristics. So f ar , WP AN can only support lo w security require- ment applications, such as athletes’ wearabl es, and critical applications, such as continuous heart monitoring de vices. These form our research moti v ation in proposing a reliable li ghtweight security mechanism for node authentication in WP ANs. 2. NODE A UTHENTICA TION IN WP ANS B ASED ON TR UST In WP AN/WB AN, the sensors and de vices might be wearable, implanted or used for personal mon- itoring. Such sensors and monitoring de vices are usually designed with minimal comple xity and lo w po wer consumption in order to maximize battery life. Ho we v er , e xisting security primiti v e operations, such as hash- Int J Elec & Comp Eng, V ol. 11, No. 2, April 2021 : 1375 – 1387 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Elec & Comp Eng ISSN: 2088-8708 r 1377 ing and encryption, require po werful processing and high resources making them unsuitable for these sensors and de vices. Therefore, in this paper , we propose a lightweight frame w ork for trust management and authenti- cation of nodes in WP AN. The frame w ork treats the WP AN as cogniti v e radio enabled wireless netw ork, and di vides nodes into tw o types, primary user (PU) and secondary user (SU). PU is a trusted node in WP AN that is ph ysically secure, and SU is a node that cogniti v ely operates through the WP AN without causing harmful interference to the PU. In addition, there is a de vice that al lo ws other wireless de vices to connect to a wired or wireless netw ork using W iFi, or related standards. In addition, Further , our frame w ork consists tw o units called base stations, the primary user base station (PUBS) and secondary user base station (SUBS). 2.1. System model and ar chitectur e Figure 1 depicts the proposed trust based authent ication WP AN architecture by dynamically di viding nodes into tw o groups: primary and secondary . This architecture fits well for WP AN due to the mobility of the netw ork and the dynamics of its topology that allo ws nodes to be part of the netw ork based on se v eral aspects, including time, and location. Figure 1. System architecture for the trust-based authentication frame w ork for WP AN/WB AN The k e y components of the frame w ork include the (Base station) which acts as a point of c o nt act between primary nodes as well as secondary nodes. The architecture contains on primary user base station (PUBS) that connects primary nodes, and a secondary user bas e station (SUBS) that connects secondary nodes. In addition, the certificate aut hority (CA) is used to maintain trust v alues for all nodes as well as for updating the trust repository whene v er requested from the PUBS or SUBS. In addition, it plays a role in the authentication process. Finally , T rust repository acts as a database for nodes’ trust v alues. Since the trust v alue is publicly kno wn, its inte grity is achie v ed storing a pri v ate trust v alue for e v ery node locally . The pri v ate trust v alue is only visible to the CA so that it can be v alidated ag ainst an y malicious modification. 2.2. Operation of trust-based authentication framew ork This section sho ws ho w nodes can join the WP AN as secondary nodes using the proposed archi tecture. Figure 2 sho ws the steps, where the node request is made by the node to the WP AN. The request is processed into the BS, which i n turn calculates a trust v alue for the node, and communicate it with the CA. The CA first checks for biasing, and if detected, the biasing algorithm is used to handle this situation. Otherwise, the authentication decision is made based on the calculated trust v alue. The decision is communicated, and the trust v alue is updated if necessary . The first step of the propos ed method is to perform trust calculation for candidate nodes. When a node w ants to use the netw ork resources i.e. as a secondary node, the SUBS calculates its corresponding trust v alue. this is achie v ed by asking all member nodes of the SUBS to assign a trust v alue to the candidate node. Once e v ery member communicates back it s recommended v alue, based on history of the node, the SUBS aggre g ates the recei v ed trust v alues and obtains one for the candidate node. If the node is deemed trustw orth y , then it is either authenticated by the SUBS or the request is forw arded to the PUBS. In this case, the PUBS A trust-based authentication fr ame work for security of WP AN using network slicing (Sazia P arvin) Evaluation Warning : The document was created with Spire.PDF for Python.
1378 r ISSN: 2088-8708 also calculates the candidate node’ s trust v alue to decide i ts eligibili ty to access the required resources. This is done through the trust based authentication frame w ork process as sho wn in Figure 2. An y calculated trust v alue of the candidate node must be communicated to the CA to process it. Once a trust v alue is calculated, authentication process is started. Authentication is performed bas ed on trust v alue and a predefined threshold. While processing trust v alue through the CA, a biasing check is performed, i f the calculated trust v alue is found biased, then SUBS handle this situation by marking nodes with improper trust v alue is biased. T rust calculation, authentication, and biasing are discussed in more detail in the follo wing tw o sections. N od e  R eq u es t B S  T ru s t   C alcu la t ion T ru s t   p r ocessed   in   C A  B ias  D e t ect ion   Alg or it h m B ias R esolu t ion   Alg or it h m Acc ep t   N od e Au t h en t ic a t ion   D e cisio n R ej ect   N od e Figure 2. T rust based authentication frame w ork 3. TR UST EV ALU A TION In a real life scenario, lar ge number of connected de vices, such as wearable de vices, smart de vices, WBSN nodes, de vices with tags, etc get connected dynamically making trust calculation becomes a continuous process. W e define trust in WP AN as a de gree of reliabi lity and security that can be ensured when a SU requests to access an y PU’ s node. In this conte xt, trust is calculated for authenticating a SU’ s request and to determine whether the SU can be allo wed to use a PU’ s free spectrum or other netw ork resources without causing an y security breach or malicious attack in the WP AN. In our proposed frame w ork, we calculate the candidate SU node’ s trust comprehensi v ely using the direct trust, indirect trust and inte grated trust e v aluation models, which are described ne xt. Our proposal dif fers from the methods adopted in literature [24, 25] as it is uniquely modeled for WP AN. Figure 3 sho ws a scenario for trust e v aluation models in our proposed frame w ork by depicting the dif ferent trust relationships between a candidate SU node and other member PU nodes. The trust v alues calculated using three trust e v aluat ion models, namely direct trust, indirect trust and inte grated trust, with trust v alues are in the range of 0 (complete distrust) and 1 (complete trust). In the ne xt subsections, we e xplain the process adopted in calculating the candidate node’ s trust v alue using v arious scenarios of the member node relationships established. N o d e   1 N o d e   4 N o d e   3 N o d e   2 D i re ct   t ru s t D i re c t   t ru s t D i re ct   t ru st I n d i re c t   t ru st D i r e ct   t ru s t C andida t e  Node Figure 3. A scenario for trust e v aluation models Int J Elec & Comp Eng, V ol. 11, No. 2, April 2021 : 1375 – 1387 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Elec & Comp Eng ISSN: 2088-8708 r 1379 3.1. Dir ect trust v alue calculation In this model, we e v aluate the direct trust of a candidate node by proposing a computation method for determining a quantitati v e direct trust v alue. The direct trust v al u e of a node is calculated by other member nodes if a direct relationship has been established between them via some past interaction and cooperation e xperiences. Let us denote the direct trust v alue as T D ir ecttr ust . In Figure 3, node 2 represents the candidate SU node, and it has established direct communication links with both node 1 and node 4. Hence, node 1 and node 4 will use the direct trus t e v aluation model based on the past communication link to calculate the candidate node’ s trust v alue. A candidate node’ s direct trust v alue is determined based on the member nodes that ha v e established a direct communication link or cooperation. In a dynamic WP AN, the relationships between nodes k eep chang- ing. Hence, the trust v alues determined by the member nodes ha v e to be constantly monitored by the base station according to the users’ multi-attrib ute trust v alues. A historic record of information about all the past communication links established are maintained in a table of cooperation records as sho wn in T able 1. The candidate node’ s trust v alue is calculated based on its attrib ute v alues. In our proposed approach, each at- trib ute has three v alues associated, namely the number of successes ( S i ; i = 1 ; 2 ::::n ) , the number of f ailures ( F i ; i = 1 ; 2 :::n ) and the amount of cooperation ( C i ; i = 1 ; 2 ; ::::n ) . W e assume equal v alues assigned between the users for cooperati v e/non-cooperati v e beha vior during their interaction process. T able 1. Cooperation record table Attrib utes Success F ailure Cooperation Sum A 1 S 1 F 1 C 1 A 2 S 2 F 2 C 2 .... .... .... .... A n S n F n C n W e define the cooperation sum used in T able 1 as the total sum of the number of successes and f ail ures of a candidate node’ s request or e v ent and is represented by C i = S i + F i ; i = 1 ; 2 ; :::n . The trust v alue for attrib ute A i can be computed based on the v alues in T able 1 and then can be used to calculate the candidate node’ s o v erall t rust v alue (denoted by T D ir e ct tr ust ) with n attrib utes A i ; i = 1 ; 2 ; ::n by combining the trust v alues for each attrib ute T A i as follo ws: T D ir ec t tr ust = n P i =1 T A i n P i =1 T A i + n P i =1 (1 T A i ) ; w her e T A i = S i C i ; (1) 3.2. Indir ect trust v alue calculation In order to e v aluate the indirect trust of a candidate node in the absence of an y direct communicati on link wi th another node, we consider the recommendations from the neighboring member nodes. The past interactions between the surrounding member nodes and the candidate node is used to establish the indirect trust v alue of the candidate node. In this model, each member node that does not ha v e an y past communication link or cooperation e xperience with the candidate node will then mak e a request to other neighboring member nodes for pro viding recommendations about the candidate node. By this method, the candidate node’ s trust is calculated indirectly Let us denote such an indirect trust v alue as T I ndir ec t tr ust . As sho wn in Figure 3, node 3 has no direct communicati on link with the candidate node (node 2). Ho we v er , node 3 has a direct communication with node 1 and node 4. Hence, node 3 can f acilitate a request t o node 1 and node 4 t o mak e a recommendation about the candidate node. Therefore, the indirect trust e v aluation model will be adopted for node 3 to compute the candidate node’ s trust v alue. According to the second scenario of our trust e v aluation model, where the member node does not ha v e direct communication link or cooperation established with the candida te node, an indirect trust v alue is calcu- lated. In this case, the member node mak es a request to other neighboring member nodes for recommendations about the candidate node. W e di vide these surrounding nodes into three dif ferent types, namely reliable nodes (trustw orth y nodes), unkno wn nodes and unreliable nodes. Reliable nodes are those surrounding nodes that ha v e pro vided trust w orth y recommendations in the past. Let ( T r el i abl e ) denote the trust v alue recommended A trust-based authentication fr ame work for security of WP AN using network slicing (Sazia P arvin) Evaluation Warning : The document was created with Spire.PDF for Python.
1380 r ISSN: 2088-8708 by such reliable nodes. Unkno wn nodes are t hose surrounding nodes from whom the member node has not solicited recommendations in the past. Let ( T unk now n ) represent the trust v alue recommended by thes e un- kno wn nodes. Based on history of e v ents, if a neighboring node has pro vided incorrect recommendations in the past, it is considered as an unreliable node. Let ( T unr el iabl e ) denote the trus t v alue recommended by unreliable nodes. In the Indirect T rust v alue calculation, the member node considers the recommendations from reliable and unreliable nodes only and not from the unreliable nodes. In addition, a weight f actor which represents the de gree of utility/importance based on the e v ents that were monitored and quantified are gi v en to distinguish between the recommendations from relia ble and unkno wn nodes. It is logical to e xpect a higher weight f actor assigned to reliable nodes’ recommendations as that of unkno wn nodes. The trust v alues of both T r el iabl e and T unk now n are required to be first calculated in order to determine the candidate node’ s Indirect T rust v alue. The process of calculating trust v alue from reliable n odes consists of tw o steps: i) the member node retrie v es the trust v alues s tored locally from the reliable nodes the y ha v e directly e v aluated; and ii) the member node recei v es trust v alues from reliable nodes who ha v e pro vided the recommendations about the candidate node’ s trust v alue. The member node combines all these trust v alues and computes T r el iabl e using 2. T r el iabl e = n r eliable P i =1 T M R i T R C i n r el ia bl e (2) where T M R i denotes the trust v alue from member node (M) to i th reliable node (R); T R C i denotes the trust v alue from reliable node (R) to candidate node (C) and n r el iabl e denotes the total number of reliable nodes. Ne xt, the trust v alues from unkno wn nodes T unk now n are calculated using 3. T unk now n = n unk now n P k =1 T U C k n unk now n (3) where T U C k denotes the trust v alue from k th unkno wn node to candidate node and n unk now n denotes the total number of unkno wn nodes. Let us denote a weight W r el iabl e to be allocat ed to the reliable nodes’ trust v alue T r el iabl e and a weight W unk now n to be a ssigned to unkno wn nodes’ trust v alue T unk now n . W e use the approach gi v en in [Reference thesis] to allocate the weights, W r el ia bl e and W unk now n . W e adopt t he traditional weighted approach to calculate the candidate node’ s o v erall Indirect T rust v alue as follo ws, where W r el iabl e + W unk now n = 1 and W r el iabl e ; W unk now n 2 [0 ; 1] : T I ndir ectt r ust = T r el iabl e W r el iabl e + T unk now n W unk now n (4) 3.3. Integrated trust v alue calculation It is typical that WP AN e xhibits dynamic situations from time to time, establishing direct as well as indirect communication links bet ween the nodes. An inte grated trust e v aluation model is proposed here for situations where both direct and the indirect trust v alues ha v e bee n computed. In this model, we combine both direct trust and indirect trust v alues from member nodes in order to compute the candidate node’ s o v erall trust v alue indirectly . Let us denote the inte grated trust v alue as T ig . In Figure 3, both node 1 and node 4 has established both direct and indirect communication links with the candidate node (node 2). Therefore, node 1 and node 4 will adopt the inte grated trust e v a luation model to combine the direct trust as well as Indirect T rust v alues computed from both links for determining the candidate node’ s o v erall trust v alue. In the third scenario of trust e v aluation model of our proposed frame w ork, the Inte grated T rust v alue of a candidate node is calculated for situations when the candidate node has established both direct and indirect communication links with member nodes. In this case based on the requirements of a certain task, each member node assigns dif ferent weights using the weighted approach. Let us denote W dt as the weight for the direct trust v alue and W it as the weight for the indirect trust v alue. Then, the candidate node’ s Inte grated T rust v alue is calculated by the follo wing equation, where W dt + W it = 1 and W dt ; W it 2 [0 ; 1] T ig = W dt T dt + W it T it (5) Int J Elec & Comp Eng, V ol. 11, No. 2, April 2021 : 1375 – 1387 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Elec & Comp Eng ISSN: 2088-8708 r 1381 These calculations determine if a cooperation between nodes ha v e tak en place and each member node updates the Inte grated T rust v alue of its cooperation node (candidate node) accordingly . The SUBS can no w mak e a decision on an SU’ s request to authenticate access to PU’ s netw ork based on the abo v e calculated trust v alue. While the abo v e trust e v aluation model w orks for e xisting SU in the netw ork, it does not cater to situations when a ne w user who has securely joined a secondary netw ork of the WP AN mak es a request to access the PU’ s netw ork, This is because the trust v alue may not be a v ailable with the PUBS or other PUs. Hence, we propose a bootstrapping method to address such a ne w SU case scenario in the ne xt subsection. 3.4. Bootstrapping of trust v alue calculation W e propose a boot strapping method for the PUBS to determine the trust v alue for a ne wly joined SU under tw o main methods: i) T riangular T rust v alue calculation; and ii) Reference T rust v alue calculation. The algorithm for bootstrapping a ne w SU’ s trust v alue is pro vided in the follo wing three steps: A ne wly joined SU requests the SUBS to access the PU’ s free spectrum. This request is subjecti v e to the trust v alue determined by the SUBS and is based on: i) its joining process to the secondary netw ork; and ii) its beha viour pattern observ ed for a certain period of time. On successful completi on of this authentication process, the SUBS sends the request to the PUBS for further action. When the PUBS recei v es the request from the SUBS for the SU to access the primary netw ork, the authentication is based on the SU’ s trust v alue. At this stage, s ince the SU node has no trust v alue with either the PUBS or the other PUs, triangular trust v alue calculation method is in v ok ed, which is based on the trust relationship between the PUBS and SUBS. There are tw o pathw ays: i) a trust relationship e xists between PUBS and SUBS-SU’ s trust v alue is based on the triangular trust v alue calculation method; or ii) no trust relationship e xists between the SUBS and PUBS-trustw orth y member nodes in the secondary netw ork are used by the PUBS and the SU’ s trust v alue is based on reference trust v alue calculation method. W e pro vide a detailed algorithm of trust v alue calculations under both triangular trust and reference trust methods in the follo wing subsections. 3.4.1. T riangular trust v alue calculation This bootstrapping method is used when some trust relationship e xists between the SUBS and PUBS. The triangular trust calculation method is used here to determine t he trust v alue of a ne w SU when it has a relationship with the SUBS b ut not with the PUBS. Let us ass ume the trust relationship between PUBS ! SUBS; SUBS ! SU1 for calculating the trust v alue of the SU node (SU1), and denote T P U B S ;S U 1 as the trust v alue of the PUBS for the SU node (SU1). Assuming the trust v alue between PUBS and SUBS to be 0.8, and the trust v alue between SUBS and SU1 to be 0.7, we ha v e T P U B S ;S U B S = 0 : 8 and T S U B S ;S U 1 = 0 : 7 , we can calculate the T riangular T rust v alue between the PUBS and SU1 as follo ws: T P U B S ;S U 1 = T P U B S ;S U B S T S U B S ;S U 1 = 0 : 8 0 : 7 = 0 : 56 3.4.2. Refer ence trust v alue calculation This bootstrapping method is used in cases where there is no relationship between PUBS and SUBS. The reference trust v alue calculation for a ne wly joined SU is based on the recomme n da tions from other users. The dif ference here from the indirect trust v alue calculation method is that the SUs and not the PUs request for recommendations from the PUBS. Here, v arious trust v al ues recei v ed are collected and the a v erage of these v alues a re computed to determine the o v erall trust v alue for the ne w SU. As sho wn in Figure 4, let us assume the trust relationship between dif ferent nodes such that PUBS trusts SU2 and SU3 with a v alue of 0.5 and 0.6, respecti v ely , and SU1 who is a ne wly joined SU has a trust v alue of 0.5 with SU2 and 0.4 with SU3. I n this case, the a v erage trust v alue between the PUBS and SU1 is determined as follo ws: T P U B S ;S U 1 = ( T P U B S ;S U 2 T S U 2 ;S U 1 + T P U B S ;S U 3 T S U 3 ;S U 1 )) = 2 = (0 : 5 0 : 5 + 0 : 6 0 : 4) = 2 = 0 : 249 = ) 0 : 25 Finally , the PUBS decides to declare whether the SU node (SU1) is trustw orth y or not based on whether the abo v e computed trust v alue (either through T riangular T rust relationship or Reference T rust rela- tionship) is greater than the predefined threshold v alue ( T thr eshol d ) or not. Hence, the predefined threshold v alue plays a major role in determining the minimum le v el of trust required by the PUBS. A trust-based authentication fr ame work for security of WP AN using network slicing (Sazia P arvin) Evaluation Warning : The document was created with Spire.PDF for Python.
1382 r ISSN: 2088-8708 PU BS S U 3 S U 1 S U 2 0 . 5 0 . 5 0 . 6 0 . 4 0 . 2 5 Figure 4. A ne w SU node within a reference trust relationship 4. A UTHENTICA TING AND BIASING PR OBLEM RESOLUTION If a node is eligible to access the netw ork resources, then, it will authenticated by the BS. This is done by ha ving the SUBS compares the computed trust v alue, T , ag ainst the predefined threshold, ( T thr eshol d ) . The candidate node is authenticated only if its trust v alue is greater than the required threshold, otherwise it request is rejected. On the other hand, the SUBS may forw ard the request to the PUBS, which also obtains the node’ s trust v alue and v alidates it ag ainst the authentication threshold. The node is authenticated only if it has trust v alue higher than the threshold. There are se v eral adv antages of adopting this mechanism. First, the netw ork can support tw o le v els of authentication. Second, certain nodes might be authenticated for certain resources b ut not for others, and finally , the threshold of authentication can be adjusted in order to relax or strict access based on ho w critical the application is. Biasing may occur only at the SUBS, therefore, it is processed by the SUBS by asking the CA to pro- vide the current candidate node’ s trust v alue, if there is one. The SUBS also obtain a trust recommended v alues from member nodes. The CA v alidates the candidate node’ s trust v alue it has through the public and pri v ate repositories, and communicates a v alidated one to the SUBS. The SUBS compares the computed recei v ed v alue from CA with the calculated one through members. If there is a dif ference, then the SUBS mark the candidate node’ s trust v alue as biased. SUBS then check the v alue communicated from members node before and after the biasing occurs. The SUBS then reports nodes that pro vide dif ferent trust v alues are ‘malicious node’ or ‘biased by a malicious node’. This information is communicated to all of SUBS member nodes. T dt = n P i =1 T A i n P i =1 T A i + n P i =1 (1 T A i ) = 0 : 57 + 0 : 71 + 0 : 42 (0 : 57 + 0 : 71 + 0 : 42) + (1 0 : 57) + (1 0 : 71) + (1 0 : 42) = 0 : 56 (6) T r el iab l e = n r eliable P i =1 T M R i T R C i n r el iabl e = 0 : 45 0 : 5 + 0 : 6 0 : 45 + 0 : 5 0 : 7 3 = 0 : 28 (7) 5. PERFORMANCE EV ALU A TION W e assume that none of the nodes is biased. The input parameters for the tw o netw orks are the number candidate nodes, the number of nodes in the netw ork, and the threshold for trust. The first netw ork acts Int J Elec & Comp Eng, V ol. 11, No. 2, April 2021 : 1375 – 1387 Evaluation Warning : The document was created with Spire.PDF for Python.
Int J Elec & Comp Eng ISSN: 2088-8708 r 1383 as secondary netw ork and has 5 nodes. The second netw ork acts as a primary netw ork and also has 5 member nodes and one base station. W e also assume that each has 3 criteria for trust. W e also assume that a threshold trust v alue of 0.6 is initially used. T rust v alue calculation is conducted by members in the tw o netw orks using direct trust, and then communicated with the base station. The final trust v alue is them calculated by the base station and sent to the CA. The final trust v alue is then used to check for biasing mak e a decision about user authentication. In this section we demonstrate authentication base d on the trust v alue, where we consider three cases for node v alidation in both netw orks, in the first we address node authentication is granted in the secondary netw ork, then node authentication is granted in the primary netw ork, and finally , node authentication is denied. F or authentication in the secondary netw ork, we assume that node 2 is t he candidate node in the secondary netw ork, and that the rest of nodes will pro vide their trust recommendation about node 2 to the secondary netw ork base station. It is also assumed that nodes are f air and not biased. W e conducted simulation by generating 100 repetiti v e cases for the success and f ailure for each time period for three criteria, where trust v alue for the candidate node is assigned using equations 1 and 6. The trust v alues of the candidate node recommended from the four nodes in the secondary netw ork for dif ferent time periods are sho wn in T able 2. Therefore, the a v erage trust v alue of the candidate node for e v ery criteria can be calculated. F or instance for the first criteria it is equal to : 0 : 81+0 : 32+0 : 76+0 : 99 4 = 0 : 72 . Then, the final trust v alue of the candidate node calculated from the using the three dif ferent criteria as : 0 : 72+0 : 67+0 : 45 3 = 0 : 61 . T able 2. Recommended trust v alue calculated from nodes in the secondary netw ork using three criteria Candidate Node Node number in ‘Netw ork 1’ Criteria 1 Criteria 2 Criteria 3 4*Node 2 1 0.818 0.996 0.645 3 0.321 0.045 0.998 4 0.763 0.316 0.959 5 0.996 0.855 0.487 In the ne xt step, the computed trust v alue is compared with the trust threshold and the decision is made based on this comparison, as sho wn in T able 3. Since he computed final trust v alue of 0.61 is lar ger than the threshold v alue of 0.6, the SUBS authentica tes the candidate node to accept its request to use the netw ork resources or forw ards its request to the secondary netw ork as sho wn in T able 3. T able 3. Authentication of candidate node in the secondary netw ork Candidate node T rust V alue of Candidate node Final trust v alue Threshold v alue threshold ? Decision Criteria 1 Criteria 2 Criteria 3 3* Node 2 0.72 0.67 0.45 0.61 0.6 Y es Request is Netw ork 1’ authenticated or forw arded to ‘ ‘Netw ork 2’ F or authentication in the primary netw ork, we demonstrate an authentication request for a candi d a te node for the resources in the primary netw ork. W e assume that the pri mary netw ork has fi v e no de s and three criteria, where node 5 is assumed to be the candidate node. The member nodes of the prim ary netw ork calculate the trust v alue for node 5 using direct trust from dif ferent time periods using three criteria as illustrated in T able 4. The a v erage trust v alue of the candidate node for each criteria is calculated, for instance, for criteria 1 it is 0 : 59+0 : 95+0 : 76+0 : 93 4 = 0 : 81 . The base station calculates the final trust v alue using : 0 : 81+0 : 55+0 : 77 3 = 0 : 71 , which is then communicates it to the CA. This v alue is also used compared with the threshold of 0.6, and as a result, the candidate node is granted access to the primary netw ork as illustrated in T able 5. In this e xample we sho w request rejected case, where the same steps in the first case are perform ed, where node number 2 in the secondary netw ork is the candidate node. T able 5 sho ws the final calculated trust v alue of 0 : 3 is less than the threshold v alue, therefore, the request is not authenticated in the secondary netw ork. In other w ords, the candidate node is not considered v alid and in its o wn netw ork, therefore, the base station of the secondary netw ork does not forw ard the request to access the primary netw ork resources. Ne xt, we consider the biased nodes case where a number of biased nodes tak es part in the authentication process of certain nodes. This e xample will sho w ho w biasing is detected, and ho w the base station resolv es this iss ue along with the CA. W e assume that the secondary netw ork has 5 nodes, and that node 3 is the candidate node. W e will also assume A trust-based authentication fr ame work for security of WP AN using network slicing (Sazia P arvin) Evaluation Warning : The document was created with Spire.PDF for Python.
1384 r ISSN: 2088-8708 that some member nodes will intentionally assign biased trust v alues for the candidate node. Once biasing is detected, resolution is performed by the netw ork as demonstrated. T able 4. Recommended trust v alue calculated from nodes using three criteria in primary netw ork Candidate Node Node number in ‘Netw ork 2’ Criteria 1 Criteria 2 Criteria 3 4*Node 5 1 0.599 0.996 0.645 3 0.960 0.045 0.998 4 0.765 0.316 0.959 5 0.931 0.855 0.487 T able 5. Recommended trust v alue calculated from nodes using three criteria in primary and secondary netw orks Candidate node T rust V alue of Candidate node Final trust v alue Threshold v alue threshold ? Decision Criteria 1 Criteria 2 Criteria 3 3* Node 2 in 0.81 0.55 0.77 0.71 0.6 Y es Request is ‘Netw ork 1’ authenticated Node 4 in 0.21 0.33 0.47 0.33 0.6 No Request is ‘Netw ork 1’ Declined The candidate node’ s trust v alue is calculated by the member nodes in ‘Netw ork 1’, where all member nodes are f air . F or criteria 1, four nodes in ‘Netw ork 1’ assign a trus t v alue to the candidate node accordingly , as sho wn in T able 6 sho ws trust v alue for candidate node 3 before biasing. The final trust v alue for the candidate node as calculated by the base station in the secondary netw ork is 0 : 8056+0 : 7842+0 : 5032 3 = 0 : 6976 . This v alue is communicated to the CA, which stores it as the same for pri v ate v alue and public v alue for each node in the database before biasing. Assuming that member node 5 is biased, and that it will assign f alse trust v alues for the candidate node, the base station calculates the final trust v alue for node 3 in netw ork 1 bec omes 0.69, 0.93, and 0.57 for the three criteria with final v alue of 0.80, which is dif ferent from the trust v alue computed before biasing tak es place. Once this trust v alue is communicated with the CA, it will be detected as biased due to lar ge dif ference. In order to resolv e this problem, the CA identifies all the trust v alues for all member nodes in both netw orks in the repository and forw ards the information to the base station in the secondary netw ork where biasing w as initiated. This e xample sho ws ho w the biased v alue is detected in the secondary netw ork. Once a biasing is detected, the case station checks for the trust v alue assigned by its nodes for all criteria as illustrated in T able 7, which sho ws that node 5 w as biased with its trust assignment. Therefore, the secondary netw ork base st ation communicates this information to all nodes in the netw ork and e xcludes the biased node from further contrib utions in the trust calculation. T able 6. T rust v alue calculated in secondary netw ork using three criteria Candidate Node number Criteria 1 Criteria 2 Criteria 3 Node in ‘Netw ork 1’ 4*Node 2 1 0.701 0.998 0.555 2 0.983 0.787 0.582 4 0.973 0.983 0.182 5 0.584 0.376 0.725 T able 7. T rust v alue calculated for biasing detection in secondary netw ork for dif ferent criteria Criteria Criteria Node number T rust v alue before biasing T rust v alue after biasing Similar Decision 4*1 Node 1 0.7016 0.7016 Y es Not biased Node 2 0.9833 0.9833 Y es Not biased Node 4 0.9737 0.9737 Y es Not biased Node 5 0.5843 0.9999 No Biased 4*2 Node 1 0.9982 0.9982 Y es Not biased Node 2 0.7866 0.7866 Y es Not biased Node 4 0.9833 0.9833 Y es Not biased Node 5 0.3760 0.9999 No Biased 4*3 Node 1 0.5554 0.5554 Y es Not biased Node 2 0.5826 0.5826 Y es Not biased Node 4 0.1822 0.1822 Y es Not biased Node 5 0.7253 0.9999 No Biased Int J Elec & Comp Eng, V ol. 11, No. 2, April 2021 : 1375 – 1387 Evaluation Warning : The document was created with Spire.PDF for Python.