  Complex cryptographic protocols are often constructed from simpler
building-blocks. In order to advance quantum cryptography, it is important to
study practical building-blocks that can be used to develop new protocols. An
example is quantum retrieval games (QRGs), which have broad applicability and
have already been used to construct quantum money schemes. In this work, we
introduce a general construction of quantum retrieval games based on the hidden
matching problem and show how they can be implemented in practice using
available technology. More precisely, we provide a general method to construct
(1-out-of-k) QRGs, proving that their cheating probabilities decrease
exponentially in $k$. In particular, we define new QRGs based on coherent
states of light, which can be implemented even in the presence of experimental
imperfections. Our results constitute a new tool in the arsenal of the
practical quantum cryptographer.

Quantum Physics