ObjectiveThe continuous variable quantum key distribution protocol has drawn much attention because of its easy preparation of light source, higher detection efficiency than single photon detector and good compatibility with passive optical communication networks. The measurement device-independent protocol effectively eliminates all known or unknown side-channel attacks in the detection side. However, the initial experiment that encodes information on the amplitude and phase quadratures using coherent or squeezed states, indicated a relatively complexity compared to the unidimensional modulation. The unidimensional continuous variable quantum key distribution protocol has the characteristics of simple modulation process, low cost-effectiveness, and less consumption of random numbers. Realization condition of unidimensional modulation protocol is more convenient than that of two-dimensional Gaussian modulation. For the purpose of simplifying the system and reducing experimental complexity, a novel protocol is proposed, achieving relatively higher security key rate and longer distances.MethodThis paper introduces unidimensional continuous-variable measurement-device-independent quantum key distribution using squeezed states and the security performance of the proposed scheme is comprehensively analyzed including both symmetric and asymmetric transmission distances. For the convenience of analyzing the security of protocol, an entanglement-based (EB) scheme is proposed to provide a comprehensive proof. Based on the measurement device-independent protocol, general coherent state preparation is expanded to the squeezed state. Taking into account the realistic conditions, a detailed comparison investigates the impact of introducing light source noise and detection noise on the protocol's security performance. Furthermore, the impact of squeezing parameter on the performance of the protocol is explored for both asymmetric and symmetric distances. The performance of the protocol is also investigated under the eavesdropper's one mode attack and two mode attack.Results and DiscussionsOur simulation results reveal the existence of optimal modulation variances and squeezing parameters at different transmission distances. These results provide a theoretical framework for achieving optimal secure key rates and secure transmission distances in experimental implementations, thereby facilitating the practical realization of the proposed scheme. Based on these results, we can achieve relatively higher secure key rate by selecting the appropriate parameter for adapting different application scenarios. This could pave the way for greater cost-effectiveness and a simpler way to implement the protocol in the future. As theoretical analysis mentioned about imperfect source and detectors, it may be insufficient to guarantee the realistic implement. It is possible that these imperfections can be compensated by optical phase-sensitive amplifiers.ConclusionThis paper presents a protocol for unidimensional continuous-variable measurement-device-independent quantum key distribution using squeezed state. By adjusting the modulation variance and squeezed parameter, we can achieve more efficient and longer transmission distances while ensuring the actual security performance of the system. This research also clarifies that the influencing mechanism of source noise and detected noise on the performance of the protocol. We can selectively tune the modulation variance and squeezed parameter towards different application scenarios.