Namecoin is a distributed domain name system based on the Bitcoin technology. Namecoin extends Bitcoin to add transactions for registering, updating and transferring domain names. Namecoin provides an alternative to the existing domain name system (DNS), in which names can be taken from their owners by groups that control the DNS servers.
Unlike the current DNS, Namecoin avoids central authorities and issuers. Namecoin uses a distributed database spread across nodes of a peer-to-peer network to journal transactions, and uses digital signatures and proof-of-work to provide basic security functions, such as ensuring that domain names can be transferred only by their owner.