The paper is interesting but is based on some assumptions that in specific
situations are not realisable. However, the limitations are addressed
explicitly in specific section dedicated to a discussion of what is
necessary for a complete implementation. Since there are some aspects
that cannot be implemented I cannot understand hoe authors discuss the
"acceptable performance" of the system.
The author(s) wrote that the system is decentralized on the
smartphones in the abstract; however, this is not discussed in any
sections in the paper. Moreover, although obviously, this scheme cannot
be implemented in today’s technology, it is claimed that this scheme
can provide an acceptable performance of the distance-bounding protocols
on smartphones.