Single photon counting applied to Quantum Key Distribution (QKD)
Quantum cryptography is an emerging technology using the properties of quantum physics to achieve high levels of security proved superior to traditional security technologies.
In quantum cryptography, quantum keys, unbreakable by conventional methods, are secretly distributed between two parties apart. Quantum key distribution (QKD) allows to ensure absolute confidentiality of transmitted key because the security level is guaranteed by a physical principle in contrast to traditional cryptography based on algorithms.
In fiber optic communication, a principle of quantum key transmission is to reduce the light to the lowest possible level, the photon. An accurate measurement of photons is necessary, and requires the use of single photon counters, as well as a single-photon sources and sources of photon pairs twins. One of the most critical parts of QKD is the use of highly sensitive single photon counting detectors which is not only used to receive the distributed secret keys, but also to detect eventual ''hackers''.
The photon counter SPD_A from AUREA Technology was originally designed for quantum key distribution at the telecom wavelength 1550 nm. Thanks to its high detection performance (very low noise and high efficiency), government agencies, financial institutions, data centers or companies with distributed offices, can encrypt their confidential communication with the highest level of security over distances exceeding 100 km.