## 5 Analysis and Discussion
### Security Aspects  
There are several security attacks that can be tested on our proposed cryptosystem; the first trial can be a brute force attack. * Brute Force Attack  
The adversary can know the primary public key of MRBS \(P_{MRBS}\) and NTR \(P_{NTR}\), while it will also know the base point \(B\) and Elliptic curve \(EC\). Now, the challenging task is to determine the private key \(K_{MRBS}\) or \(K_{NTR}\); if one of them can be found, the entire communication can be compromised; for example, if the MRBS is compromised, the entire underlying system is as well, and if the NTR is compromised, the small cell network that the NTR is making will be compromised. Our proposed algorithm uses ECC as the key selection, while the size of the key is \(\geq 384\), making it more secure against modern attacks. ECC is based on DLP, which states that  
\[a^{x}=M \tag{13}\]  
where \(M\) is a known Multiplicative Group, \(a\) is a generator term from \(M\), \(x\) is an element such that \(x\in M\). Therefore, the problem is to find the key with the following DLP equations of the following type:  
\[P_{MRBS}=\ K_{MRBS}\times B \tag{14}\]  
Where adversaries must find the \(K\) time point multiplication with base point \(B\) such that \(P\) is achieved, while the Elliptic curve works on an elliptic equation that effects the rotation with \(K\), so the complexity becomes greater when the key is rotated \(M\) times. Second, if this communication is cracked, our proposed algorithm uses session-based encryption using the same algorithm so that cracking occurs for each session. Thus, complexity will accumulate in each session. The opposite is true if one of the sessions is hacked (which is not possible), so only the session communication may become compromised and not the remaining sessions. * [PERSON]'s rho method [35]  
This is an intelligent way to attack that is also lightweight in nature. It requires parallelization and random walk. It has been observed that it makes it possible to find the secret key by reducing to the square root of the attack. It has been theoretically shown in a few studies that with \(10^{4}\) computers, a key can be cracked in less than two years [36]; similarly, [PERSON] et al [37] presented a scheme for solving 112 bits primes using a games console; all are based on the theoretical assumption of collusion. Our algorithm uses a key size of greater than 512, which is equal to 15,360 bits of RSA [9; 37]. Thus, for the first key, even if the square root is taken, it will be fairly impossible to crack the problem. Figure 3 shows that the key size for the ECC does not increase considerably, but the key size for the RSA increases dramatically. * Replay Attack  
Replay attacks allow the adversary to store the message and then send the message at some other interval. This can result in various issues that lead to loss of assets, tracks, and other information. To avoid this attack, as can be seen in Equation (9), the time stamp is introduced. Depending on thechannel condition of each session, the TTL is determined, so if the TTL is more than the current time difference with the message time, the message is considered fresh, as shown in the following equation:  
\[If\ (Current_{time}-Message_{time})>TTL \tag{15}\]  
Then, the message is fresh; else, message \(M\) is not fresh. Thus, the replay attack cannot be performed on our proposed algorithm. There are several types of attack, such as TCPReplay, but as we have introduced the time stamp and nonce, the attack will be caught. * M-I-T-M Attack  
For a M-I-T-M attack that can result in interleaving or a DoS attack, we consider the Needam-schroder protocol [38] and let NTR be a rouge relay:  
\[\text{MRBS}\rightarrow\text{NTR}\ \text{MRBS}\rightarrow\text{NTR}\ E[P_{N\!R}(C_{M\!B}, \ \text{S},\ P_{M\!B},\text{TS})]\]  
Here, instead of the NTR, if some other adversary receives the message, it will not be able to open the message or even gain access to the cipher text. Thus, this attack will fail.