In this paper we analyze the mathematical foundations of IOTA, a cryptocurrency for the Internet-of-Things (IoT) industry. The main feature of this novel cryptocurrency is the tangle, a directed acyclic graph (DAG) for storing transactions. The tangle naturally succeeds the blockchain as its next evolutionary step, and offers features that are required to establish a machine-to-machine micropayment system.
S. Handley. Proceedings of the 1994 IEEE World Congress on
Computational Intelligence, 1, page 154--159. Orlando, Florida, USA, IEEE Press, (27-29 June 1994)