Kvantsidekanalid

Kvantsidekanalid are channels of information leakage that arise from unintended couplings between a quantum system and its environment or from imperfections in quantum devices. They can reveal information about quantum states, keys, or computations without breaking the protocol's formal security assumptions. They are a concern in quantum cryptography, computation, and metrology.

They take various forms, including timing information, power draw, electromagnetic or optical emissions, thermal signatures, and cross-talk between qubits and control electronics. Leakage can occur during state preparation, transmission, measurement, or readout, and arises from imperfect isolation, detector non-idealities, or nonuniform device responses.

In quantum key distribution (QKD), common side channels include multi-photon emissions enabling photon-number splitting, detector vulnerabilities such as blinding and efficiency mismatch, time-shift attacks that exploit timing differences, and Trojan-horse attacks that probe internal states with light. These exploit hardware weaknesses rather than breaking quantum theory.

In quantum computing, side channels may arise from control lines, power supplies, or thermal fluctuations that couple to qubits, or from leakage during readout. They can reveal information about computational states or operations and are addressed with isolation, shielding, and careful circuit and software design.

Defensive approaches include device-independent or measurement-device-independent QKD to reduce hardware trust, decoy-state methods to limit information leakage, optical and electromagnetic shielding, attenuators and isolators, randomized timing, and formal testing and certification of components.

The study of kvantsidekanalid is part of broader quantum security and engineering practice, reflecting the need to align theoretical security proofs with practical hardware realities in quantum technologies.