Tham khảo tài liệu 'artificial intelligence for wireless sensor networks enhancement part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Distributed Detection of Node Capture Attacks in Wireless Sensor Networks 349 This SPRT can be written as yn s So n accept Hq and terminate the test. yn S1 n accept H1 and terminate the test Sq n yn S1 n continue the test process with another observation. Where ln Í 1 nln 1 0 lni-A nln 1 0 1 a 1 Ở1 a 1 Ở1 So n IX. S1 n 1 ln ln - ln ln 1 0 1 0 ỞQ 1 ỞQ a and ệ are the user-configured false positive and false negative rates respectively. If the SPRT terminates in acceptance of Hq node u restarts the SPRT with newly received messages from v. However if the SPRT accepts H1 u terminates the SPRT on v decides v as a captured node and disconnects the communication with v. The pseudocode for the SPRT is presented as Algorithm 1. Algorithm 1 SPRT for replica detection INITIALIZATION t 1 y 0 INPUT Nt OUTPUT accept the hypothesis Hq or H1 compute So t and S1 t if Nt Q then y y 1 end if if y S1 t then accept the alternate hypothesis H1 and terminate the test end if if y So t then accept the null hypothesis Hq and initialize t to 1 and y to Q return end if t t 1 4. Security Analysis In this section we first present the detection capability of our scheme and then discuss about the limitations of node capture attacks under the presence of our scheme and countermeasures against some possible attack strategies against our scheme. In the SPRT the following types of errors are defined. a error probability that the SPRT leads to accepting H1 when Hq is true. Ỉ error probability that the SPRT leads to accepting Hq when H1 is true. Since Hq is the hypothesis that a node u has not been captured a and ft are the false positive and false negative probabilities of the SPRT respectively. According to Wald s theory Wald 2QQ4 the upper bounds of a and Ỉ are a - r-7 s ĩ ã 4 350 Smart Wireless Sensor Networks Fig. 1. Upper limit on detection probability vs. P when a . Fig. 2. Upper limit on detection probability vs. P when a . Distributed Detection of Node Capture Attacks in Wireless .
