Quantum cryptography has undergone substantial growth and development within the multi-disciplinary field of quantum information in recent years. The field is constantly advancing with new protocols being developed, security measures being improved, and the first practical applications of these technologies being deployed in optical fibers and free space optical beams. In this paper, we present a comprehensive review of a cutting-edge metropolitan-scale protocol for continuous-variable quantum cryptography. The protocol allows an arbitrary number of users to send modulated coherent states to a relay, where a generalised Bell detection creates secure multipartite correlations. These correlations are then distilled into a shared secret key, providing a secure method for quantum secret-sharing. This novel approach to quantum cryptography has the potential to offer high-rate secure multipartite communication using readily available optical components, making it a promising advancement in the field.