  We present a protocol for the amplification and distribution of a
one-time-pad cryptographic key over a point-to-multipoint optical network based
on computational ghost imaging (GI) and compressed sensing (CS). It is shown
experimentally that CS imaging can perform faster authentication and increase
the key generation rate by an order of magnitude compared with the scheme using
computational GI alone. The protocol is applicable for any number of legitimate
user, thus, the scheme could be used in real intercity networks where high
speed and high security are crucial.
