## 5 Discussion  
As stated above, many efforts have been made to surmount the highlighted issue, but plenty of the suggested proposals are quite heavy to be applied for general usage. First, the AES cipher can be mentioned as a robust algorithm that offers strong security, but the algorithm's operations are complicated to handle by RFID tags. At this scale, reducing round numbers can fix this problem. The TEA cipher seems resource-friendly; unfortunately, the cipher has several security flaws, since it does not offer adequate security strength. Applying ECC along with several techniques provides a strong security level, where both the data confidentiality and integrity are well proven, but it is burdensome for tags' and readers' resources. Challenge-response schemes are suitable as an efficient solution for tags with computational limitations; nevertheless, the PRNG and CRC techniques used to build the schemes do not lend vigorous certainty if an attacker has good computation capabilities. The dynamic keys concept is another endeavor proposed to address the RFID environment security issue, but this solution is intricate to employ because each tag is configured individually. Homomorphic cryptography appears as a good construct, but it is onerous to apply to conventional RFID systems with built-in memory storage because of its mathematical operations. For this reason, it is widely utilized when the system has external storage capacity (cloud storage). Post-quantum schemes can also be used, but this is unlikely; the level of complexity of these solutions is significant and needs considerable mathematical understanding for implementation. Watermarking and deep learning methods might offer some security features; even so, these require specific hardware such as high-resolution cameras (facial recognition) and fingerprint sensors to gather biometric information, a fact that is regarded as costly for regular applications. Hashing algorithms can offer the wanted system integrity, but some algorithms such as MD5 and SHA-1 are becoming vulnerable to some attacks, so carrying them out may cause security breaches and lead to sensitive information leakage. Among other solutions, some lightweight proposals sound relevant if applying some changes to their internal algorithmic cores in order to enhance their security performance; We can mention the IDEA, Present, Mickey, and Multi-factor authentication schemes, where the systemmust be reviewed to  
Figure 5: Graphical representation of Table 5 suggested cryptosystems. become superior cost-security tradeoff benchmarks. Based on these findings, there are plenty of suggestions that can be given as follows:  
* **Healthcare applications:** Due to the real-time demand of data, low-cost cryptosystems are preferred, and we can mention the Tiny Encryption Algorithm (TEA) and Mickey ciphers. However, some critical changes must be made at the core of both algorithms because of the low resistance of to a manifold of types of attacks such as side channel attacks and the weak avalanche abilities, which reduce the cryptosystem's trustworthiness. For this reason, advanced or improved versions of both algorithms are suggested. * **E-payment:** Because of the high sensitivity of the exchanged data between smart cards, readers, and connected databases that are related to banks, the higher the security, the more confident the system becomes. Therefore, it is suggested to employ the public key infrastructure concept within digital signatures to provide authenticity and confidentiality to users. * **E-voting:** A card can be issued to every eligible citizen to vote in his/her country's elections. This can be a one-time utilization card, where robust cryptosystems are implemented to avoid vote corruption. Homomorphic cryptography along with other algorithms such as AES can be combined to offer the utmost possible security. * **Other applications:** The cost, performance, and security trade-off must always be kept in mind by developers.