The Ethereum Classic cryptocurrency is based on the original block chain Ethereum. In June 2016, DAO, the first smart contract, knows about one million flights. Hard Fork (Hard Fork) was held on July 20, 2016 to solve this problem. The hard fork has been changed in the block chain so that the two block chains have been separated (the modified channel and the original channel). They say the chain is winning when the majority of the chain is following one of the two chains. Today the winning chain is the Ethereum chain and the original chain continues to exist under the name Ethereum Classic. As a result, all ETHs at addresses before the hard fork also exist on the ETC channel