Fig. 3
From: QKD protected fiber-based infrastructure for time dissemination
The experimental setup used for the encryption of the time signal with the QKD: at Site B, a maser generates a \(10\,\hbox {MHz}\) clock reference and a 1 PPS signal, which are transmitted to Site A via WR-PTP. At Site A, the WR-PTP signal is encrypted using a function generator with QKD-derived keys provided by the KMS. The encrypted WR-PTP signal is then sent back to Site B via the same classical channel. At Site B, the \(10\,\hbox {MHz}\) signal is decrypted using the “decoder” function generator, while a PPS generator is exploited to realize the 1PPS signal measured with TIC1. Analogously, TIC2 measures encrypted WR-PTP signals. The WR-PTP signals exchange and the classical communication of the QKD devices are multiplexed over the same classical channel, while the QKD quantum channel is used to securely exchange encryption keys, which are managed by the KMS at both sites.
