Hasan Iqbal

Quantum key distribution offers unconditionally secure keys for communicating parties. Although using high-dimensional quantum systems in QKD protocols does offer considerable advantages, which has been extensively shown in different experiments, analytical security proofs for high-dimensional protocols are not abundant. This is partly because many QKD protocols lack certain ``symmetry'' in terms of the parties' capabilities and responsibilities, which complicates security proofs. In this work, we consider one such protocol and provide analytical security proof and compare our results against prior work showing an advantage of our method. We also develop a continuity bound for conditional quantum entropies which is pertinent to our analysis here and may have applications in other scenarios also.