This paper presents a quantum key distribution (QKD) protocol using Gaussian-modulated coherent states and homodyne detection, which is secure against Gaussian individual attacks. The protocol involves transmitting Gaussian-modulated coherent states (laser pulses with a few hundred photons) through a quantum channel and performing homodyne detection at the receiver end. The protocol uses reverse reconciliation followed by privacy amplification to extract a secret key. The reverse reconciliation technique is secure for any line transmission and is more effective than traditional reconciliation methods in QKD. The protocol is demonstrated experimentally, achieving a net key transmission rate of about 1.7 Mbps for a loss-free line and 75 kbps for a line with 3.1 dB losses. The protocol is efficient for any line transmission and can operate beyond the 3 dB loss limit of traditional QKD protocols. The security of the protocol is based on the principles of quantum mechanics, particularly the Heisenberg uncertainty principle, and is not reliant on entangled or squeezed states. The protocol involves Alice and Bob exchanging Gaussian key elements, which are then processed to extract a secret key. The security of the protocol is ensured by the use of reverse reconciliation, which allows Alice to guess what was received by Bob rather than Bob guessing what was sent by Alice. This gives Alice an advantage over a potential eavesdropper, Eve, regardless of the line loss. The protocol is implemented using a continuous-wave laser diode at 780 nm wavelength, with a repetition rate of 800 kHz. The data is organized in bursts of 60,000 pulses, and the overall homodyne detection efficiency is 0.81. The protocol is efficient for any line transmission and can operate beyond the 3 dB loss limit of traditional QKD protocols. The protocol is secure against Gaussian individual attacks and is not reliant on entangled or squeezed states. The protocol is efficient for any line transmission and can operate beyond the 3 dB loss limit of traditional QKD protocols. The protocol is secure against Gaussian individual attacks and is not reliant on entangled or squeezed states.This paper presents a quantum key distribution (QKD) protocol using Gaussian-modulated coherent states and homodyne detection, which is secure against Gaussian individual attacks. The protocol involves transmitting Gaussian-modulated coherent states (laser pulses with a few hundred photons) through a quantum channel and performing homodyne detection at the receiver end. The protocol uses reverse reconciliation followed by privacy amplification to extract a secret key. The reverse reconciliation technique is secure for any line transmission and is more effective than traditional reconciliation methods in QKD. The protocol is demonstrated experimentally, achieving a net key transmission rate of about 1.7 Mbps for a loss-free line and 75 kbps for a line with 3.1 dB losses. The protocol is efficient for any line transmission and can operate beyond the 3 dB loss limit of traditional QKD protocols. The security of the protocol is based on the principles of quantum mechanics, particularly the Heisenberg uncertainty principle, and is not reliant on entangled or squeezed states. The protocol involves Alice and Bob exchanging Gaussian key elements, which are then processed to extract a secret key. The security of the protocol is ensured by the use of reverse reconciliation, which allows Alice to guess what was received by Bob rather than Bob guessing what was sent by Alice. This gives Alice an advantage over a potential eavesdropper, Eve, regardless of the line loss. The protocol is implemented using a continuous-wave laser diode at 780 nm wavelength, with a repetition rate of 800 kHz. The data is organized in bursts of 60,000 pulses, and the overall homodyne detection efficiency is 0.81. The protocol is efficient for any line transmission and can operate beyond the 3 dB loss limit of traditional QKD protocols. The protocol is secure against Gaussian individual attacks and is not reliant on entangled or squeezed states. The protocol is efficient for any line transmission and can operate beyond the 3 dB loss limit of traditional QKD protocols. The protocol is secure against Gaussian individual attacks and is not reliant on entangled or squeezed states.