## 5 Results and Discussion
### Simulation Results
#### 5.1.3 Message Tamper Attacks  
As described above, the malicious node can either alter data, time or location of the legitimate message. In this particular attack, we focused on the data of the message. Thus, whenever an attacker received a message, the content is tampered by this malicious nodes into garbage data which is then shared with the neighboring vehicles.  
Figure 10(a) shows the end-to-end delay of the network in presence of the malicious nodes which are changing the content of the messages. First, it can be seen concluded that E2E delay of the network increases with the increase in malicious nodes. Second, high E2E delay is achieved by the network in presence of distributed malicious nodes due to their wide spread attack scope. On the other hand, fleet of malicious nodes are launching attacks which are limited to specific location, therefore, the low E2E delay is achieved as legitimate messages are shared in a large section of the network. As an illustration, for a network with 50% malicious nodes, network containing distributed attackers achieves 69.91% high E2E delays than fleet attackers.  
The ability of the network to transmit legitimate messages within the network via CDR is depicted Figure 10(b). It shows that CDR decreases when the number of malicious nodes increases within the network. As the malicious nodes are changing the content of the legitimate messages, therefore increasing such malicious nodes results in low values of CDR as the ratio of garbage data increases  
Figure 10: (a) Dropped Messages (b) Packet Loss Ratio.  
within the network. Further, the attack pattern also affects CDR. It can be seen that when the network contains attackers in fleet, high CDR is achieved as compared to distributed malicious nodes. This is due to the fact that fleet of attackers are located in particular section of the network, thus, only a portion of the network is affected by these attacks. In the meantime, legitimate messages are transmitted between the nodes in large section of the network, thus high CDR is achieved. On the other hand, due to wide-spread attack vector of the distributed malicious nodes, large section of the network is affected. As a result the network achieve low CDR values. Further, figure also depicts that for 50% malicious nodes, the network with fleet attackers achieves about 41.48% high CDR as compared to distributed attackers.  
Next, the number of compromised messages is shown in Figure 11(a). It can be seen that the high number of messages are tampered and compromised in presence of high number of malicious nodes. Further, high number of messages in the network are in compromised state in presence of fleet of malicious nodes. As the attackers are launching attack together, therefore, network is affected more in presence of such attackers. For 50% malicious attackers, the network with fleet vehicles are compromising about 12.23% more packets than distributed attackers.  
Figure 11: (**a**) End-to-End Delay (**b**) Content Delivery Ratio.  
Figure 12: (**a**) Compromised Messages (**b**) Packet Loss Ratio.  
The impact of the attackers on the network in terms of lost packets in depicted in Figure 12b. Ideally, small value of PLR is desired. Figure shows that network is affected more when malicious nodes are increased within the network. Moreover, the attack pattern of the malicious nodes also results in different PLR. The distributed malicious nodes affect the network more as high PLR is achieved in the network. As mentioned earlier, these attacker have high impact on the network due to their wide-range of attack vector. As a result, high number of legitimate packets are lost within the network. On the other hand, fleet of attacker are only targeting at the specific portion of the network, thus, packets are lost in such location only. For 50% distributed attackers, the network experience about 6.89% more lost as compared to the network containing fleet attackers.