A blockchain is a cryptographically encoded database that is publicly shared. Imagine a spreadsheet, where each page is encrypted so that only the appropriate parties can view the un-encoded data, but anyone can have a copy of that encoded data. Each page in the spreadsheet is its own record, called a block, with a link, called a hash, back to the previous block.

This publicly shared spreadsheet of information is called a distributed ledger. Anyone can have a copy of the encoded ledger and add to it. By having multiple copies, this ensures that previous blocks in the chain cannot be altered. Any changes to one copy will be called out as inconsistent in the other copies and overridden with the original data, preventing falsified records.