  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.
