Experimental demonstration of a hybrid authenticated key exchange integrating QKD and PQC in a single protocol

Currently deployed public-key infrastructure faces an imminent threat in the face of quantum computers. It is expected that, given sufficiently large and reliable quantum computers, dedicated quantum algorithms such as Shor's algorithm [1] will completely break cryptographic schemes whose security is based on the discrete logarithm and integer factorisation problems. This includes widely deployed cryptographic algorithms such as RSA, Diffie-Hellman and elliptic-curve based approaches which underpin the security of existing electronic communications. Therefore, the secrecy of highly sensitive information currently being exchanged is under significant threat as messages can be recorded in bulk and decrypted in the future in so-called harvest-and-decrypt attacks.