Quantum Key Distribution (QKD) protocols are designed to establish a shared secret key by combining classical and quantum mechanical methods, guaranteeing security even against adversaries with unlimited computational power. However, all widely-known QKD protocols require an authenticated classical channel, which is usually implemented using a pre-shared key (PSK) and a stream cipher, meaning that QKD protocols are not information-theoretically secure (ITS). In this paper, we propose a novel ITS QKD protocol, which generates a shared authenticated bitstream, which can be safely used for OTP encryption.