Blockchain

Blockchain is the world's leading software platform for digital assets, offering the largest production block chain platform in the world. The first blockchain was conceptualized by Satoshi Nakamoto in 2008 and implemented the following year as a core component of the digital currency bitcoin, where it serves as the public ledger for all transactions. A blockchain database is managed autonomously and registered transactions cannot be altered retroactively.
It is a distributed database that maintains a continuously growing list of ordered records called blocks. Each block contains a timestamp and a link to a previous block. By design, blockchains are inherently resistant to modification of the recorded data. Once recorded, the data in a block cannot be altered retroactively. Blockchains are "an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way.
Blockchains are suitable for the recording of events, medical records, other records management activities, identity management, and transaction processing. Various regulatory bodies in the music industry have started testing models that use blockchain technology for royalty collection and management of copyrights around the world. Previously unimagined applications, from digitally recorded property assets to regulatory compliance and trading are now actively being developed and deployed. Automated voting systems may prove to be the ultimate blockchain-based technology beyond bitcoin.

Blockchain is a large electronic system, on top of which you can build applications. Currency, like bitcoin is one of those applications. Millions of users and hundreds of thousands of merchants currently use bitcoin digital currency. You can buy and sell bitcoins on PayPal and buy with your credit card or cash. Bitcoin is the decentralized, global, democratized, highly secure cryptocurrency. It use has grown immensely since it began and this global currency is completely separate from any government and its price is not subject to political manipulation. Last time I looked, one bitcoin was worth over a thousand US dollars.