"The blockchain is the software that both powers and regulates cryptocurrency bitcoin. In its most basic form, it records ownership of bitcoin — money — and transactions — one person paying another.
Transactions are signed off by the parties involved using the software, then added to the blockchain, a long string of code that records all activity.
Once other transactions are added on in front of an exchange, the transaction is stuck there forever and can't be changed, in the same way you can't change a brick once it's been built into a wall.
The software cuts out the need for a "trusted middleman" to sit in between parties in a transaction as it acts as that middleman. This makes transactions quicker, cheaper, and easier when compared to the current banking system."
Business Insider- Oscar Williams-Grut
Sept 15, 2015