## 6 IoT Security Solutions
### ECC-Based  
Fog server-based authentication scheme is developed by [PERSON] et al. in [229]. Secret information is stored in the memory of RSUs, Vehicles, and fog servers from TA. It uses ECC-based key management. It uses XOR and hash operations for developing the authentication. To replace compromised nodes, it has a phase of dynamic node addition. [PERSON] et al. proposed an ECC encryption-based batch verification algorithm that has the main objective of reducing verification time [230]. It has been found that in this batch verification scheme, ten times less time is required compared to RSU only verification. When traffic is higher, then RSU allocates assistance verification terminals (AVT) based on computational power and network traffic. After verification, AVT shares a confirmation message which is finally verified by RSUs. An ECC-based certificateless aggregate signature authentication mechanism was presented by [PERSON] et al. in [231]. Combining several unique signatures on distinct messages from different vehicles into a single signature, it decreases verification time and storage requirement at RSU. It assumes the elliptic curve discrete logarithm problem is not forgeable. The vehicle generates public-private key pair upon receiving a partial secret key. [PERSON] et al. also developed an ECC-based protection protocol in [232]. It calculates its private key by summing a stored key in the TPM module and a random number to avoid a side-channel attack. RSU broadcasts the certificate every five seconds, and the vehicle verifies that and shares the signature. RSU verifies the signature for mutual authentication. TA uses two hash functions to revoke the authenticity of RSUs and vehicles. However, as each vehicle generates its own pseudo-identity, the system will not authenticate the vehicle if the PID is in the compromised list. Also, this scheme needs secured communication between RSU and TA. Here, TA works as a cloud as well. [PERSON] et al. [233] proposed an ECC-based framework to enhance the system proposed by [PERSON] et al. in [234] for mobility networks. Mobile users (MU) are connected to a home agent (HA), and when MU goes beyond the coverage area of HA, it will be connected to a foreign agent (FA). The storage cost of the framework is high as MU, HA, and FA need to store many parameters. Moreover, each FA needs to register with each HAs and also needs to have information about MUs. FAs will complete the authentication with HAs when MU makes a request. Compared to other frameworks, this requires many more calculations. In [235], [PERSON] et al. solved the flaws of the framework of [PERSON] et al. [236]. This work covers the communication between the sensor and the user via a gateway, but the communication to the server is absent here. Verification of user in sensor should be done in step two instead of step four to avoid unnecessary computation and communication in case of invalid user. The protocol could suffer from a smart card stolen attack. [PERSON] et al. 's [237] proposed a framework to work on edge data of smart grids. To secure against reply attacks, random nonces were encrypted in each stage. The smart meter used the private key to prove its identity. It is required to consider security at the hardware level. Another authentication framework was designed by [PERSON] et al. in [238]. The method covers the communication between edge devices and the smart meters. The secure communication to the control center is not presented. It is unclear how the smart meter will select edge nodes based on hashed pseudo-ID. Edge nodes could be compromised if an attacker could extract the pseudo-IDs of the edge nodes. The authentication is completed in two message flow. [PERSON] et al. in [239] showed an authentication mechanism using ECC for the vehicular network. The method needs to be optimized as it requires high computational cost and communication overhead due to complex calculations. [PERSON] et al. [240] proposed an ECC-based authentication method for Industry 4.0.