Quantum Echo Keys Theory: Secure Key Generation Using Echoed Superposition's in Feedback Quantum Circuits

Zuhair Ahmed

This work proposes Quantum Echo Keys Theory (QEK-T), a cryptographic framework in which quantum keys are generated using echoed superposition’s inside feedback-controlled quantum circuits. The protocol distributes key information across temporal measurement echoes rather than storing it in a single quantum state. Qiskit simulations on a four-qubit system demonstrate perfect recovery in ideal conditions and high resilience under realistic noise. Parametric noise sweeps confirm graceful fidelity degradation, establishing temporal echo correlation as a new security dimension in quantum cryptography.

Yadollah Farahmand, Zabialah Heidarnezhad, Х. Х. Муминов

Omar S. Mustafa, Ali H. Yousif, Dana F. Abdulqadir

The mechanism of quantum mechanics is considered as the principal method of quantum key distribution for transmitting a cryptographic key between users in unconditionally secure communication. In this paper, simulation and enhancement of the performance of SARG04 protocol have been done in terms of error correction stage using multiparity rather than single parity. In addition, the suitable length of subblock was selected depending on the values of quantum bit error rate and round number. Dynamic linear-feedback shift register circuits have been used to extend the final key. These circuits are dynamically generated by the final key. A unique linear circuit is created for each generated key.

Shinil Cho

Takuma Sasaki, Izumi Kakesu, Yusuke Mitsui +5 more

We experimentally achieve common-signal-induced synchronization in two photonic integrated circuits with short external cavities driven by a constant-amplitude random-phase light. The degree of synchronization can be controlled by changing the optical feedback phase of the two photonic integrated circuits. The change in the optical feedback phase leads to a significant redistribution of the spectral energy of optical and RF spectra, which is a unique characteristic of PICs with the short external cavity. The matching of the RF and optical spectra is necessary to achieve synchronization between the two PICs, and stable synchronization can be obtained over an hour in the presence of optical feedback. We succeed in generating information-theoretic secure keys and achieving the final key generation rate of 184 kb/s using the PICs.

Pangavhane Aditya Anil, Praveen Likhar, Ravi Shankar Yadav