# A Systematic Survey on 5G and 6G Security Considerations, Challenges, Trends, and Research Areas
## 5 Proposed Future Security Mechanisms
### Post-Quantum Cryptography
#### 5.2.2 Post-Quantum Cryptography in 5G and 6G  
The direction of computing is headed toward quantum processing, which will directly affect many current and widely used encryption methods. With access to a powerful enough machine, these traditional schemes will be rendered useless, as discussed earlier. The 5G authentication protocols are thus primed to fall victim to quantum decryption due to 5G-AKA and EAP-AKA both having a public key architecture. This realization has caused calls for the adoption of PQC into the 5G standard by NIST and other researchers. However, at present, 3 GPP does not specify standards for PQC incorporation into 5G. An article covering the migration to PQC in mobile networks details that with the current pace of PQC standardization, it is presumed that PQC will be rolled out in 5G with 3 GPP Release 19 or 20 [132] at the earliest. This will lead right into 3 GPP Release 21, which will be the first 6G standard, to be issued around the year 2030.  
Researchers have been investigating the use cases for PQC in 6G with the notion that 6G will incorporate more connected AI/ML, terahertz (THz) communications, automation, operations over Non-Terrestrial Networks (NTNs), and more. An important consideration of the use of PQC is the amount of computation required to encrypt and decrypt communications. This is a similar problem to what we currently face for resource-constrained devices, which then often leads to these devices resorting to more lightweight cryptographic algorithms. One aspect explored therefore is the usage of PQC algorithms for IoT applications that are more efficient both in terms of storage and computation. The authors of a recent 6G security survey share that lattice-based algorithms are best suited for IoT applications [133]. Since this approach uses smaller key types compared to other algorithms, it could be a candidate for use in a constrained 32-bit device. The authors do note that these are only considerations and have not yet been standardized specifically for IoT. Some performance analyses of popular PQC algorithms were conducted on a Raspberry Pi 4 to inspect the computational duration requirements for key generation, encapsulation, and decapsulation along with the signing and verification of messages [134]. Their results show that the Dilithium and Kyber algorithms, presented earlier, are the best all-around approaches for low-latency applications. With low delays, it is presumed that a resource-constrained device will have a better possibility of extended battery life while also ensuring that sufficient compute resources remain for other tasks. The authors' results have been visually recreated in Figures 11 and 12 from [134]. Computational resources will be a major consideration for the rollout and adoption of any 6G standards, as it aims to incorporate a higher volume of IoT devices along with a diverse set of personal, business, and medical devices. This will also be important for the continued expansion of NTNs targeted by 6G in order to maintain reasonable latency benchmarks when communicating with, or through, satellite constellations.  
Figure 11: Results from [134] for popular PQC algorithms evaluating keypair signing and verification performance on a Raspberry Pi 4.