IOTA is a distributor ledger with the technology-based data structure called “Tangle” which retains similarities to block chains while removing the block structure in favor of a directed acyclic graph structure. IOTA cryptocurrency was launched in 2015. In IOTA the tangled architecture allows for infinite scaling whereby speed is limited by the number of transactions on the network
Method of functioning
IOTA network is functioning through every user who generates a transaction on the network must do a small amount of proof-of-work to validate two other transactions. This enables a zero transaction fee model in which the only cost paid by users is the proof-of-work needed to validate two transactions per transaction initiated.
IOTA runs a centralized close source Coordinator which is to provide a milestone checkpoint to resist against attacks on the network while the network is young. The coordinator has been a source of discussion on decentralization for young distributed ledgers