Hashgraph is a distributed ledger technology that has been described as an alternative to blockchains. The hashgraph technology is currently patented, and the only authorized ledger is Hedera Hashgraph. The native cryptocurrency of the Hedera Hashgraph system is HBAR.
Unlike blockchains, hashgraphs do not bundle data into blocks or use miners to validate transactions. Instead, hashgraphs use a “gossip about gossip” protocol where the individual nodes on the network “gossip” about transactions to create directed acyclic graphs that time-sequence transactions. Each “gossip” message contains one or more transactions plus a timestamp, a digital signature, and cryptographic hashes of two earlier events. This makes Hashgraph form an asynchronous Byzantine Fault-Tolerant (aBFT) consensus algorithm.