## 6 Evaluation of the Proposed Protocol
### Security Evaluation
This attack is identified when we analyze the vulnerabilities of the LEACH-based secure routing protocols in shown in Section 4. Figure 8: Relating each possible attack with the corresponding attacked security property. Furthermore, we check each attack against the security objectives it attempts to compromise. In Section 3, the explained security properties are data confidentiality, data integrity, data freshness, source authentication and availability property. Figure 8 is the diagram that summarizes our approach in the evaluation. We relate each attack with the targeted security property. By identifying each attack based on the security property it attempts to compromise, we can simply recognize how each protocol addresses the listed possible attacks. Readers may refer to Table 2 that presents the summary of countermeasures we use for our protocol to fulfill the security requirements. Table 3 summarizes our evaluation on the list of possible attacks against SLEACH, SecLEACH, MS-LEACH and the proposed protocol from secure routing point of view. Reader may refer to the Section 3.3 for the explanation. The first attack under observation is the passive attack, eavesdropping. In this attack, an adversary with a strong receiver can eavesdrop and intercept the transmitted packets. SLEACH does not prevent this attack since it does not provide confidentiality services, especially for the sensor readings and the aggregated result. SecLEACH also poses the same problem. In the other hand, MS-LEACH uses encryption to protect those data, and even the schedule messages are encrypted as well. The proposed protocol provides encrypted transmission for the sensitive data. Hence eavesdropping can be tackled. The second attack is the message tampering. It attacks the data integrity properties. SLEACH suffers from this attack. This attack can target the join request message, the schedule message or the sensor reading transmissions of SLEACH. This is because its join request and schedule message transmission do not employ data integrity protection algorithms. In the case of its sensor reading transmissions, the transmissions are guarded by the keyed MAC using the key shared between the cluster member node and the BS, and furthermore, the sensor reading is not the input of the MAC computation. This allows adversaries to tamper with the message within cluster transmission, especially the sensor reading part, without being detected by the CH. If we observe the performance of SecLEACH against this attack, then SecLEACH also allows message tampering to take place on advertisement messages and schedule messages. MS-LEACH and the proposed protocol prevent this attack from happening. MS-LEACH uses MAC in every transmission to guarantee data integrity. The proposed protocol uses digital signatures or MAC to guarantee the data integrity of each message. Readers may refer to Table 2.  
The third is the replay attack. In facing replay attacks, all these protocols are equipped with countermeasures. Though the approaches are different, all can prevent replay attacks. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Possible Attacks Observed** & **SLEACH** & **SecLEACH** & **MS-LEACH** & **Proposed Protocol** \\ \hline Eavesdropping & No & No & Yes & Yes \\ Message tampering & No & No & Yes & Yes \\ Replay & Yes & Yes & Yes & Yes \\ Ordinary nodes impersonation & No & Yes & No & Yes \\ CHs impersonation & Yes & No & Yes & Yes \\ Schedule disruption & No & No & Yes & Yes \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Possible attacks addressed, in comparison with other secure routing protocols. As for the next two attacks, they are both node impersonation attacks but with different targeted nodes. The ordinary nodes impersonation means the adversary impersonates ordinary nodes using any valid identity while the CHs impersonation means the targeted nodes are the CHs.