• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.1
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• pp.75-86
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• 2023

Public key cryptography algorithm such as RSA and ECC, which are commonly used in current financial transaction services, can no longer guarantee security when quantum computers are realized. Therefore it is necessary to convert existing legacy algorithms to Post-Quantum Cryptography, but it is expected that will take a considerable amount of time to replace them. Hence, it is necessary to study a hybrid method combining the two algorithms in order to prepare the forthcoming transition period. In this paper we propose a hybrid session key exchange protocol that generates a session key by combining the legacy algorithm ECDH and the Post-Quantum Cryptographic algorithm NTRU. We tried the methods that proposed by the IETF for TLS 1.3 based hybrid key exchange, and as a result, it is expected that the security can be enhanced by applying the protocol proposed in this paper to the existing financial transaction session protection solution.