It is a hard fork of Bitcoin , the open source cryptocurrency. This type of attack makes it possible to manipulate the blockchain ledger on which transactions are recorded, and to spend the same digital coins more than once. For enhanced security, most of the assets are kept in the offline cold storage. Namecoin Namecoin aims to «[free] DNS, identities, and other technology» related to the infrastructure of the internet. Over the longer term, bitcoin gold will conduct research on smart contracts and blockchain democracy, as well as develop a decentralized fiat-crypto brokerage network. Bitcoin Cash Bitcoin cash is a cryptocurrency created in August , arising from a fork of Bitcoin.