Secure key exchange scheme: a DNA computing-based approach to resist MITM in DHKE.

Diffie-Hellman key exchange (DHKE) protocol was a pioneering work and considered as a new direction in the field of cryptography though it is not an encryption protocol. DHKE is a method to exchange the keys securely, based on the discrete logarithm problem. It has applications in internet security protocols including SSL, IP Sec and SSH. The major issue with DHKE is its vulnerability to man in the middle attack (MITM). Various techniques have been proposed to resist the MITM including digital signatures. This paper proposes DNA computing-based encryption techniques to resist MITM in DHKE. DNA cryptography builds on the concepts of biomolecular computations which are considered as one of the emerging directions in the cryptography. The proposed methodology also includes an encryption technique based on DNA-based codebook, secret sharing and DNA cryptography to exchange parameters securely. The security analysis of the proposed scheme is evaluated by theoretical analysis. Formal analysis of the proposed protocol is done using Scyther and all the modelled claims are validated and positive results are obtained.