## 4 Structure of SFrame Video Conferencing System
### SFrame's Key Management System
This mechanism satisfies the integrity requirement through signing with GPKI-based authentication and the confidentiality requirement through encryption, resulting in E2 EE security. Moreover, we expect this mechanism to securely share session keys even in the face of the escalating threat posed by quantum computers. Therefore, the security of video conferencing systems can be improved. The proposed PQC protocol for E2 EE in a GPKI-based video conferencing system appears to serve as valuable reference material for enhancing the On-Nara video conferencing system based on the Korea GPKI. However, as there is currently no established Korean standard for PQC, the application of a specific PQC KEM algorithm may necessitate future modifications for its usage in video conferencing systems. Therefore, the application of a specific PQC algorithm to the proposed protocol is left for future studies. In conclusion, we hope this document will be referenced when users are considering the application of PQC KEM to future video conferencing systems. Conceptualization, Y.P. and Y.Y. ; Methodology, Y.P. ; Validation, Y.Y., J.-S.K., H.Y., J.R. and Y.-R.C. ; Formal analysis, Y.P. and Y.Y. ; Investigation, Y.P., H.Y., J.R. and Y.-R.C. ; Resources, Y.P. and Y.Y. ; Data curation, Y.P. and Y.Y. ; Writing--original draft preparation, Y.P. ; Writing--review and editing, Y.P. and Y.Y. ; Visualization, H.Y., J.R. and Y.-R.C. ; Supervision, Y.Y. and J.-S.K. All authors have read and agreed to the published version of the manuscript. This work was supported by the Institute of Information & Communications Technology Planning & Evaluation (IITP) grant funded by the Korean government (MSIT) (No.2021-0-00046, Development of next-generation cryptosystem to improve security and usability of the national information system). Not applicable. The authors declare no conflict of interest. ## Abbreviations \begin{tabular}{l l} ACME & automatic certificate management environment \\ AS & Authentication Service \\ CA & certification authority \\ DTLS-SRTP & Datagram Transport Layer Security for Secure Real-time Transport Protocol \\ E2 EE & end-to-end encryption \\ eBACS & ECRYPT Benchmarking of Cryptographic Systems \\ ECDH & Elliptic Curve Diffie-Hellman \\ ECDSA & Elliptic Curve Digital Signature Algorithm \\ EdDSA & Edwards-curve Digital Signature Algorithm \\ \end{tabular} 

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