The paper introduces a novel approach to quantum key distribution (QKD) called measurement device independent QKD (MDI-QKD). This method addresses the significant challenge of detector side-channel attacks in conventional QKD systems, which can compromise security. MDI-QKD not only eliminates all detector side channels but also doubles the secure transmission distance compared to conventional QKD systems using lasers. The proposal is implemented with standard optical components and can operate over highly lossy channels with low detection efficiency. Unlike full device-independent QKD, MDI-QKD does not require near unity detection efficiency or a qubit amplifier, and it achieves a much higher key generation rate. The security of MDI-QKD is demonstrated through a detailed analysis, showing that it can tolerate high optical losses and imperfections in the preparation process. The authors also present a proof-of-concept experiment to verify the feasibility of using independent lasers for phase randomized weak coherent pulses, which are essential for the MDI-QKD protocol. Overall, MDI-QKD offers a significant advancement in practical QKD systems by bridging the gap between theoretical security proofs and real-world implementation.The paper introduces a novel approach to quantum key distribution (QKD) called measurement device independent QKD (MDI-QKD). This method addresses the significant challenge of detector side-channel attacks in conventional QKD systems, which can compromise security. MDI-QKD not only eliminates all detector side channels but also doubles the secure transmission distance compared to conventional QKD systems using lasers. The proposal is implemented with standard optical components and can operate over highly lossy channels with low detection efficiency. Unlike full device-independent QKD, MDI-QKD does not require near unity detection efficiency or a qubit amplifier, and it achieves a much higher key generation rate. The security of MDI-QKD is demonstrated through a detailed analysis, showing that it can tolerate high optical losses and imperfections in the preparation process. The authors also present a proof-of-concept experiment to verify the feasibility of using independent lasers for phase randomized weak coherent pulses, which are essential for the MDI-QKD protocol. Overall, MDI-QKD offers a significant advancement in practical QKD systems by bridging the gap between theoretical security proofs and real-world implementation.