What is Blockchain?

• It is like a database duplicated thousand of times across a network of computers, in which the network of computers have access to the database at the same time to regularly update the said database;
• Information are shared (and continually reconciled) throughout the whole network; and
• Data are accessible to anyone - no centralized version exists for hacker to target to corrupt.

How Blockchain Works?

I think it is wonderfully shown on the picture below:


Source