Digital currency based on public key encryption. Monetary units of cryptocurrency are intangible and take the form of a chain of data blocks (blockchain) linked together. Blockchain integrity is ensured by including in each block encrypted information about the previous one. This protects the system from hacking and the unauthorized addition of new blocks. Cryptocurrencies are decentralized, meaning that there is no single server that controls transactions. Instead, information about all transactions is distributed equally among all cryptocurrency holders.