Laser-pumping attack on QKD sources

For the first time, we demonstrate a new type of attack on QKD systems based on laser pumping of a photon source. It includes injection of cw laser emission into a source at a wavelength that shorter than the system operating one. Particularly, we show that laser emission at 1310 nm induces increase in photon number at 1550 nm, changes in pulse shape and width. The QKD risk evaluation due to laser-pumping attack is presented.