Secure Wireless Multihop Transmissions by Intentional Collisions with Noise Wireless Signals

Transcription

1 Int'l Conf. Wireless etworks ICW'16 51 Secure Wireless Multihop Transissions by Intentional Collisions with oise Wireless Signals Isau Shiada 1 and Hiroaki Higaki 1 1 Tokyo Denki University, Japan Abstract In wireless ultihop counication, data essages are transitted fro a source wireless node to a destination one along a wireless ultihop transission route consisting of a sequence of interediate wireless nodes. Each interediate wireless node forwards data essages to its next-hop wireless node. Here, a wireless signal carrying the data essage is broadcasted by using an oni antenna and it is not difficult for a eavesdropper wireless node to overhear the wireless signal to get the data essage. Soe researches show that it is useful to transit noise wireless signal which collide to the data essage wireless signal in order for interfering the overhearing. However, soe special devices such as directional antennas and/or high coputation power for coplicated signal processing are required. For wireless ultihop networks with huge nuber of wireless nodes, sall and cheap wireless nodes are andatory for construction of the network. This paper proposes the ethod for interfering the overhearing by the eavesdropper wireless nodes where routing protocol and data essage transission protocol with cooperative noise signal transissions by 1-hop and 2-hop neighbor wireless nodes of each interediate wireless node. Keywords: Wireless Multihop Counication, Interfering Overhearing, oise Wireless Signals, Intentional Collisions, Routing Protocol. 1. Introduction In wireless ad-hoc networks and wireless sensor networks, data essages are transitted along a wireless transission route fro a source wireless node to a destination one. A wireless transission route consists of a sequence of interediate wireless nodes which forward data essages fro its previous-hop wireless node to its next-hop one. Each interediate wireless node broadcasts a wireless signal for the data essage transission by using an oni directional antenna. Hence, it is possible for all its neighbor wireless nodes within its wireless transission range to receive the data essage. That is, the neighbor wireless node, even if it is an eavesdropper, overhears the data essage. Usually, the data essages are securely transitted by cryptography. The source wireless node encrypts a clear text and the data essage carries a cryptogra. In order for achieving the clear text fro the cryptogra in the overheard data essage, a cryptography key is required for both the destination wireless node and the eavesdropper wireless node. Especially, in sensor networks which transit and gather sensor data essages initiated by source sensor nodes with sensor and wireless counication devices to a wireless sink nodes connected to a high perforance sensor database, it is ipossible for each sensor node to ipleent highly secure cryptography ethods since its ipleentation, operation and aintenance costs should be low. Thus, even in sensor networks with siple and facile cryptography ethods, the sensor data is required to be transitted securely. For such a requireent, soe secure wireless transission ethods have been proposed as shown in the next section. One ethod requires each interediate wireless nodes to devise directional antennas and wireless signals are required to be transitted only in the specified direction by using a bea-foring ethod. The other one required each interediate wireless nodes to support high perforance signal processing with coplex calculation. However, it is difficult to introduce these conventional ethods to wireless ultihop networks consists of sall, light and cheap wireless nodes such as sensor nodes. Therefore, this paper proposes a novel secure wireless ultihop transission ethods without special hardwares such as directional antennas and/or processors supporting high perforance signal processing in each interediate wireless nodes. That is, under an assuption that wireless signals are transitted according to the unit disc odel [6] by using an oni antenna by each interediate wireless node, it akes difficult for eavesdropper wireless nodes to overhear the data essages transitted along a wireless ultihop transission route. The next section overviews related works. Our proposal for interfering the overhearing by eavesdropper wireless nodes by cooperation with neighbor wireless nodes of each interediate one is shown in Section 3. Both the routing and the data essage transission protocols are proposed. Section 4 evaluated our proposed ethod in siulation experients. 2. Related Works There are various security probles in wireless ultihop networks and a lot of solutions have been discussed and proposed. The selfish wireless node proble and the blackhole attack proble are well known peculiar probles in wireless ultihop networks. On the other hand, a so-tospeak eavesdropper proble is a coon one for wired and wireless networks and a countereasure solution is andatory. Especially in wireless networks, since all the data

2 52 Int'l Conf. Wireless etworks ICW'16 essages are carried by wireless signals which are inherently broadcasted and are easily overheard by any neighbor wireless node, uch ore advanced ethod has been required to be developed. The doinant technology is an cryptography. Due to the characteristics of the obile wireless nodes, siple and facile encryption/decryption ethods have been proposed for achieving enough security with reasonably low coputational coplexity. However, the cryptography is a ethod which akes difficult for eavesdroppers to achieve the clear text fro the cryptogra carried by the data essage. That is, it ay fall behind. Thus for taking the initiative, the ethod to ake difficult or ipossible for eavesdropper wireless nodes to overhear the data essages carrying the cryptogras is uch effective. The cobination of the ethod interfering the overhearing and the cryptography for wireless ultihop networks is expected to provide an acceptable tradeoff between required security and inevitable overhead. In wireless ultihop sensor networks and IoT (Internet of Things) consisting of huge nuber of low-power wireless nodes without coputational power enough to support highly secure counication ethods, a novel secure counication ethod not depending only on the cryptography is required. One of such ethods akes difficult for eavesdropper wireless nodes to overhear the transitted data essages by intentional collisions with noise wireless signals. Paper [2] proposes a ethod for secure wireless data essage transission under assuptions that bea foring by using directional antennas is available for all the wireless nodes (at least all the wireless nodes which is possible to transit data essages to their neighbor nodes). As shown in Figure 1, a sender wireless node s transit a wireless signal carrying a data essage to a receiver wireless node r by using bea foring such that r and only its liited neighbor wireless nodes receive it. Concurrently with the transission of the wireless signal, r also transits a noise wireless signal called a jaing wireless signal to all its neighbor wireless nodes through its oni antenna. Since the wireless signal transission range of the noise wireless signal covers the wireless signal transission range of the wireless signal carrying the data essage, no wireless node can receive the data essage itself without any collision. Here, one of the neighbor wireless node f of r forwards its receiving collided wireless signal which is the superposition of these wireless signals to r. On receipt of the collided wireless signal fro f, r reoves the original noise wireless signal fro the receiving wireless signal and achieves the original wireless signal carrying the data essage since the noise signal was transitted by r itself. This signal processing is only possible by r since no other wireless nodes even though f have the original noise wireless signal transitted by r. This sees an excellent secure counication ethod by using the intentional collisions with the noise wireless signals. However, the assuptions of the directional antennas for bea foring and high perforance processors f Fig. 1: Secure Wireless Transission by Intentional Collision with oise Wireless Signal and Forwarding Collided Message. for coplex signal processing to reove the noise wireless signals fro the collided wireless signals are not reasonable to apply to the wireless ultihop networks such as sensor networks and IoT. This is because the sensor nodes and the IoT devices ay be so sall, light and cheap and the their networks consist of huge nuber of such wireless nodes that it is difficult or ipossible to have such functionalities. Another paper [5] also discusses the ethod to realize secure wireless counication based on the noise wireless signal transissions. Here, a sender wireless node also transits a wireless signal carrying the data essage through a directional antenna for bea foring and all the other wireless nodes except for a receiver wireless node transit noise wireless signals siultaneously. Since the receipt wireless signal power is extreely high only at the receiver wireless node and the S/ ratio in the other wireless nodes is too low to receive (overhear) the data essage, the data essage is securely transitted fro the sender wireless node to the receiver one and eavesdropper wireless nodes also fail to receive the data essage. In addition to the requireent for the directional antennas in all the wireless nodes, high battery power consuption is an additional proble since all the wireless nodes are required to transit the noise wireless signals. 3. Proposal This section proposes a novel ethod for secure wireless ultihop transissions of data essages which interferes eavesdropper wireless nodes trying to achieve the clear texts carried by the data essages. Our ethod akes difficult for the eavesdropper wireless nodes to overhear the data essages which are broadcasted by interediate wireless nodes in a wireless ultihop transission route. Here, no additional special hardware such as directional antennas for bea foring and high perforance processors to support highly coplex signal processing is needed in the interediate wireless nodes. That is, the transissions of the wireless signals fro oni antennas of the wireless nodes are odeled by the unit disc odel [4].

3 Int'l Conf. Wireless etworks ICW' oise Signal Transission for Ad-Hoc Wireless Counications This section discusses the ethod for secure wireless transissions of data essages in wireless ad-hoc counication between neighbor wireless nodes, i.e., only 1-hop wireless transissions. Wireless nodes s and r are the sender and receiver ones, respectively. r is in the wireless signal transission range of s. A data essage is broadcasted by s to all the neighbor wireless node of s in the wireless signal transission range of s. Hence, r surely receives. At the sae tie all the neighbor wireless nodes including possible eavesdropper wireless nodes in the wireless signal transission range of s receive as shown in Figure2. In order to prevent to receive, noise wireless signals are introduced sae as the related works discussed in the previous section. Only noise wireless signals transitted by wireless nodes whose wireless signal transission ranges cover at least a part of the wireless signal transission range of s contribute to the secure wireless transission of fro s to r. At the sae tie, the noise wireless signal never reach r.if r is in the noise wireless signal transission range, r cannot receive due to the collision caused by and the noise wireless signal. Fig. 2: oise Wireless Signal Transissions by 1-Hop eighbor odes. This paper proposes the following conditions for a wireless node j to transit a noise wireless signal to prevent possible eavesdropper wireless node to receive the data essage transitted fro a sender wireless node s to a receiver one r (3). [oise Wireless Transitting ode j ] (1) j is a neighbor wireless node of s. j is in the wireless signal transission range of s. (2) j is not a neighbor wireless node of r. r is out of the wireless signal transission range of r. The condition (1) is a sufficient condition for the wireless signal transission range of j to cover a part of the wireless signal transission range of s. Since both and the noise wireless signal reach the wireless nodes in the coon area of both the wireless signal transission ranges, Fig. 3: oise Wireless Signal Transissions for Ad-Hoc Counication. a collision of the occurs at the wireless nodes. Hence the possible eavesdropper wireless nodes are prevented to receive by the collisions. In addition as discussed in the later subsection, the wireless nodes satisfying the condition (1) does not require any additional control essage transission to synchronously transit the noise wireless signals with fro s to r. Thus, this subsection proposes that the neighbor wireless nodes of s transit the noise wireless signals. The condition (2) is a necessary condition for the wireless signal transission range of j not to include r. Because of the assuption of the unit disc odel for the wireless signal transission range, r is out of the wireless signal transission range of j, either. Thus, the noise wireless signal fro j never reach r and no collisions between and the noise wireless signal occur at r. Thus, this subsection proposes that the neighbor wireless nodes of r do not transit the noise wireless signals. The wireless nodes satisfying both of the above two conditions are specified by the control essage transissions for the RTS/CTS control ipleented in the alost all the wireless LA protocols such as IEEE and so on. All the wireless nodes satisfying the condition (1) receive a RTS (Request to Send) control essage fro s and all the wireless nodes satisfying the condition (2) do not receive a CTS (Clear to Send) control essage fro r. The CTS control essage is transitted by r with the specified SIFS (Short Inter Frae Space) interval after receipt of the RTS control essage. Thus, if a wireless node j does not receive the RTS control essage fro r even with the SIFS interval after the receipt of the CTS control essage fro s, j transits a noise wireless signal to prevent possible eavesdropper wireless node in the wireless signal transission range of s to overhear a wireless signal carrying the data essage. In addition, since these RTS/CTS control essages carry AV inforation, it is also possible for j to specify the tie duration while the data essage is transitted fro s to r. That is,

4 54 Int'l Conf. Wireless etworks ICW'16 j can specify the tie duration for the noise wireless signal transissions. j is required to transit the noise wireless signal while the data essage is transitted fro s to s but it ust not transit it while the corresponding acknowledgent control essage is transitted fro r to s for avoidance of collisions of the wireless signal carrying the acknowledgent essage and the noise wireless signal. It is also realised based on the AV inforation. 3.2 oise Signal Transission for Wireless Multihop Counications The previous subsection proposes a ethod to prevent eavesdropper wireless nodes to overhear the data essage transitted between neighbor wireless nodes. Here, secure ad-hoc wireless counication is realized by noise wireless signals transitted by the neighbor wireless nodes of a sender wireless node out of the wireless signal transission range of a receiver wireless node. The wireless nodes and the tie duration required to transit the noise wireless signals are also specified by the RTS/CTS control essage transissions and no additional control essages are required to be transitted. However, the existence probability of the neighbor wireless nodes transitting the noise wireless signals preventing the overhearing of possible eavesdropper wireless nodes depends on the distribution of the wireless nodes, i.e., the density of the wireless nodes, and the distance s r between the sender wireless node s and the receiver one r. As shown in Figure 4, if the distance s r is relatively long, the coon area of the wireless signal transission ranges of s and r is sall and the area including the wireless nodes satisfying the conditions in the previous subsection is large. Hence, the coverage of the noise wireless signals overlapping the wireless signal transission range of s in which possible eavesdropper wireless nodes overhear the data essages is relatively high. On the other hand as shown in Figure 5, if s r is relative short, the coon area of the wireless signal transission range of s and r is sall. Since the wireless nodes in this area cannot transit the noise wireless signals which reach r, the coverage of the noise wireless signals overlapping the wireless signal transission range of s is relatively low and it is difficult to prevent eavesdropper wireless nodes to overhear the data essage. In order to solve the proble, additional wireless nodes are required to transit the noise wireless signals to iprove the coverage, i.e., the area where wireless nodes does not receive the noise wireless signals though they receive the data essage fro s is required to be reduced. It is clear that no wireless nodes in the wireless signal transission range of r can transit the noise wireless signals without collisions at r, noise wireless signal transissions by the wireless nodes out of the wireless transission ranges of both s and r are expected to be efficient. Therefore, wireless nodes out of the both wireless transission ranges of s and r are required to transit the noise wireless Fig. 4: Eavesdropper Interfering with Far Sender/Receiver Wireless odes. Fig. 5: Eavesdropper Interfering with ear Sender/Receiver Wireless odes. signals if its wireless signal transission range covers even a part of the wireless signal transission range of s. Such wireless nodes are 2-hop neighbor wireless nodes of s and are not 1-hop neighbor wireless nodes of r. Different fro the wireless nodes transitting the noise wireless signals for secure data essage transission in 1-hop ad-hoc counications discussed in the previous subsection, it is difficult to require the 2-hop neighbor wireless nodes of s to transit the noise wireless signals without additional control essages to the original RTS/CTS control. This is because the 2-hop neighbor wireless nodes are both out of the wireless signal transission ranges of s and r, additional control essages are required to be transitted to notify the to transit the noise wireless signals. In addition, it is ipossible for 1-hop neighbor wireless nodes of s to transit the additional control essage concurrently with the CTS control essage after receipt of the RTS control essage since the transitted control essage collides with the CTS control essage fro r at s. Therefore, the 2-hop neighbor wireless nodes of interediate wireless nodes being required to transit the noise wireless signals are deterined in a routing protocol which detects the wireless ultihop transission route 0... n which is a sequence of interediate

5 Int'l Conf. Wireless etworks ICW'16 55 wireless nodes fro a source wireless node s = 0 to a destination wireless node d = n. Since a certain control essages is transitted along the detected wireless ultihop transission route in ost of the ad-hoc routing protocols, each interediate wireless node transits soe control essages to notify a part of its 2-hop neighbor wireless nodes to be required to transit the noise wireless signals siultaneously with the data essage transissions. The 2-hop neighbor wireless nodes of s selected to transit the noise wireless signals according to the conditions for 1-hop ad-hoc counications described in the previous subsection are also required to transit the noise wireless signals for secure wireless ultihop counications. That is, 1-hop neighbor wireless nodes of an interediate wireless node i out of the wireless signal transission range of its next-hop wireless node i+1 is required to transit the noise wireless signals concurrently with the data essage transissions fro i to i+1. In addition to cover the wireless signal transission range of i by the noise wireless signal transission ranges to prevent eavesdropper wireless nodes to overhear the data essage, a part of the 2-hop neighbor wireless nodes are also required to transit the noise wireless signals. Though the transission ranges of the 2-hop neighbor nodes of i surely overlap the wireless signal transission range of s, they do not transit the noise wireless signals if r is their 1-hop neighbor wireless node for avoidance the collisions with the receiving data essage transissions at i+1. Therefore, for wireless ultihop data essage transissions fro a source wireless node s to a destination one d along the wireless ultihop transission route 0... n, the wireless nodes j satisfying the following conditions transits the noise wireless signals to prevent the data essages to be overheard by possible eavesdropper wireless nodes. [oise Wireless Signal Transitting ode j ] (1) A wireless node j is a 1-hop neighbor wireless node of i and in not a 1-hop neighbor wireless node of i+1. (2) j is not a 1-hop neighbor wireless node of i and i+1 either and a 2-hop neighbor wireless node of both i and i Protocol 4. Evaluation This section evaluates the coverage of the wireless signal transission ranges of the interediate wireless nodes of the wireless ultihop transission routes by the noise wireless signals transitted in accordance with the proposed ethod in siulation experients. A wireless transission range of a wireless node is 10 and its 1-hop and 2-hop neighbor nodes are randoly distributed according to the unique distribution randoness. Here average nubers of neighbor wireless nodes are 0 20 and the distance between an interediate wireless node and its next-hop wireless node is For each density of i-1 i i+1 i+2 Fig. 6: oise Wireless Signal Transissions for Wireless Multihop Counication. i-1 Jreq( i) i Rrep i+1 Jreq( ) i+1 i+2 Fig. 7: Routing Protocol with Selection of 2-Hop eighbor Wireless odes Transitting oise Wireless Signal. the wireless nodes and the distance between the successive interediate wireless nodes, the coverage is evaluated for 1,000 different distributions of the wireless nodes. For each distributions of the wireless nodes, the coverage of the wireless signal transission ranges of the interediate wireless nodes along the wireless ultihop transission routes by the noise wireless signal transission ranges for the following three cases: (1) Only 1-hop neighbor wireless nodes of the interediate wireless nodes satisfying the proposed conditions transit the noise wireless signals. (2) All the 1-hop neighbor wireless nodes of the interediate wireless nodes and the 2-hop ones satisfying the proposed conditions transit the noise wireless signals. (3) All the 1-hop neighbor wireless nodes of the interediate wireless nodes and only the liited 2-hop neighbor wireless nodes which is a neighbor of the 1- hop neighbor wireless nodes which transit the noise wireless signals transit the noise wireless signals. Figure 8 shows the results of the siulation experients. The coverage onotonically increases according to the average nubers of neighbor wireless nodes, i.e., the total

6 56 Int'l Conf. Wireless etworks ICW'16 nubers of wireless nodes in siulation and the distance between the source and the destination wireless nodes. In the (1) case, the coverage for the low density of neighbor wireless nodes and the short distance between the successive interediate wireless nodes is relatively low. However, in the (3) case, the coverage is sufficiently iproved by introduction of the noise wireless signal transissions by the 2-hop neighbor wireless nodes of the interediate wireless node. [6]Urrutia, J., Two Probles on Discrete and Coputational Geoetry, Proceedings of Japan Conference on Discrete and Coputational Geoetry, pp (1999) (1) (2) (3) Fig. 8: oise Wireless Signal Coverage. 5. Concluding Rearks This paper proposes a novel secure wireless ultihop data essage transissions by the intentional collisions with the noise wireless signals. Here, the noise wireless signals are transitted by a part of the 1-hop and 2-hop neighbor wireless nodes of the interediate wireless nodes to ake difficult for possible eavesdropper wireless nodes to overhear the data essages. To select the neighbor wireless nodes transitting the noise wireless signals, we extends AODV routing protocol with additional control essages. The results of the siulation experients show that the coverage of the noise wireless signals is reasonably high. In future work, we will further extend the routing and data essage transission protocol to increase the nuber of 2- hop neighbor wireless nodes transitting the noise wireless signals to ake ore secure wireless ultihop counications and will evaluate the perforance of our proposed ethod in wireless ultihop counication environents. References [1]Boneh, D., Dunworth, C. and Lipton, R.J., Breaking DES Using a Molecular Coputer, Proceedings of the 1st International Workshop on DA Based Coputers, pp (1995). [2]He, X. and Yener, A., Two-Hop Secure Counication Using an Untrusted Relay: A Case for Cooperative Jaing, Proceedings of the IEEE Global Telecounications Conference 2008 (2008). [3]Kanachi, T. and Higaki, H., Wireless Multihop Transissions for Secret Sharing Counication, Proceedings of the 14th IEEE International Conference on Scalable Coputing and Counications, pp (2014). [4]Kranakis, E., Singh, H. and Urrutia, J., Copass Routing on Geoetric etworks, Proceedings of the 11th Canadian Conference on Coputational Geoetry, pp (1999). [5]Tekin, E. and Yener, A., The General Gaussian Multiple-Access and Two-Way Wiretap Channels: Avhievable Rates and Cooperative Jaing, IEEE Transactions on Inforation Theory, Vol. 54, o. 6, pp (2008).