  It is well known that quantum technology allows for an unprecedented level of
data and software protection for quantum computers as well as for
quantum-assisted classical computers. To exploit these properties,
probabilistic one-time programs have been developed, where the encoding of
classical software in small quantum states enables computer programs that can
be used only once. Such self-destructing one-time programs facilitate a variety
of new applications reaching from software distribution to one-time delegation
of signature authority. Whereas first proof-of-principle experiments
demonstrated the feasibility of such schemes, the practical applications were
limited due to the requirement of using the software on-the-fly combined with
technological challenges due to the need for active optical switching and a
large amount of classical communication. Here we present an improved protocol
for one-time programs that resolves major drawbacks of previous schemes, by
employing entangled qubit pairs. This results in four orders of magnitude
higher count rates as well the ability to execute a program long after the
quantum information exchange has taken place. We demonstrate our protocol over
an underground fiber link between university buildings in downtown Vienna.
Finally, together with our implementation of a one-time delegation of signature
authority this emphasizes the compatibility of our scheme with
prepare-and-measure quantum internet networks.
