# Multi-Stage Quantum Secure Direct Communication Using Secure Shared Authentication Key
[PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H. ); [EMAIL_ADDRESS] (Z.M.H. ); [EMAIL_ADDRESS] (I.A.) [PERSON]  
1 Faculty of Computer Science and Information Technology, University Putra Malaysia, Serdang 43400, Selangor, Malaysia; [EMAIL_ADDRESS] (N.Z.H.H. ); [EMAIL_ADDRESS] (Z.M. EPR pairs as carriers to directly transmit information, while single photon QSDC combined a one-time pad protocol with the secret message [3]. The security requirement in QSDC is stricter compared to Quantum Key Distribution (QKD) since an eavesdropper must not uncover the transmitted messages. Like QKD, QSDC is divided into three approaches: Quantum entanglement [4], single-photon [5; 6], and multiple photons [7]. All of the QSDC protocols consist of four parts: Authentication, encoding, the transformation of quantum properties, and decoding, as illustrated in Figure 1. QSDC starts with the authentication process to verify the identity of [PERSON] and [PERSON]. After the successful authentication process, [PERSON] embeds the sensitive information using the proposed QSDC encoding procedure and sends the secret message over the quantum channel. To encode the information, various properties of photons can be employed such as phase, polarization, EPR quantum correlation pairs, wavelength, or quadrature components of squeezed state of light [8]. [PERSON] will then retrieve the contents of the secret message through the proposed decoding process. One of the biggest limitations of QSDC is the low transfer rate in the long-distance quantum channel [7; 9]. To overcome this limitation, a concept of multi-photon was proposed by [PERSON] [10], namely the three-stage protocol that can directly share the message over the multi-stages of the quantum channel using a rotational change in polarization.