In the last few years digital currencies have successfully demonstrated their ability to become an alternative financial instrument in many different markets. Most of the technologies available at the moment are based on the principles of Blockchain architecture, including dominating currencies like Bitcoin and Etherium. Despite its popularity, Blockchain is not the best possible solution for all scenarios. One such example is for fast micro-payments. Zold is an experimental alternative that enables distributed transactions between anonymous users, making micro-payments financially feasible. It borrows the proof-of-work principle from Bitcoin, and suggests a different architecture for digital wallet maintenance.