On the composable security of weak coin flipping

arXiv:2402.15233v1 Announce Type: cross
Abstract: Weak coin flipping is a cryptographic primitive in which two mutually distrustful parties generate a shared random bit to agree on a winner via remote communication. While a stand-alone secure weak coin flipping protocol can be constructed from noiseless communication channels, its composability has not been explored. In this work, we demonstrate that no weak coin flipping protocol can be abstracted into a black box resource with composable security. Despite this, we also establish the …

arxiv can communication composability cryptographic cs.cr protocol quant-ph random security winner