High-dimensional quantum key distribution

High-dimensional quantum key distribution (HD-QKD) is an advanced form of quantum key distribution (QKD) that extends the traditional principles of QKD to higher-dimensional quantum systems. In standard QKD protocols, information is typically encoded in two-level quantum systems, or qubits, which represent binary states (0 and 1). In contrast, HD-QKD uses higher-dimensional systems, often referred to as qudits, which can represent more than two levels.