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Security of quantum key distribution using d-level systems

Nicolas J. Cerf·Mohamed Bourennane·Anders Karlsson·Nicolas Gisin
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Abstract

We consider two quantum cryptographic schemes relying on encoding the key into qudits, i.e. quantum states in a d-dimensional Hilbert space. The first cryptosystem uses two mutually unbiased bases (thereby extending the BB84 scheme), while the second exploits all the d+1 available such bases (extending the six-state protocol for qubits). We derive the information gained by a potential eavesdropper applying a cloning-based individual attack, along with an upper bound on the error rate that ensures unconditional security against coherent attacks.

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Nicolas J. Cerf, Mohamed Bourennane, Anders Karlsson, Nicolas Gisin. 2001-07-26. Security of quantum key distribution using d-level systems. https://doi.org/10.1103/physrevlett.88.127902

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