AceCoin

A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution.Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work.