High-dimensional quantum key distribution based on qudits transmission with quantum Fourier transform

Historically, the information efficiency of the secret key in quantum key distribution (QKD) schemes based on binary signal formats was limited to 1 bit/particle. An efficient high-dimensional QKD protocol based on qudits transmission with the quantum Fourier transform is proposed. In the proposal, the inherent encoding framework provides a secure solution to key distribution, where the secret information can be hidden into the relative phases of the generated high-dimensional entangled state by performing the quantum Fourier transform and the quantum controlled-NOT gate. After the reverse operations are carried out, the key information can be decoded with the single-particle measurement chosen from two mutually unbiased bases. The secret key taking the form of the high-dimensional quantum state throughout the proposed QKD protocol enables to break the information efficiency limit. Besides, the security of the proposed QKD protocol is guaranteed by the decoy state method and it is proven to be secure even for the photon number splitting attack and the side-channel attack. The cryptographic performance in terms of security and capacity is better than that of traditional cryptographic protocols.