Blockchain is quite a complicated topic so let us break it down for you.

Apple1

Pretend we’re in the playground at little lunch and I give you an apple.  Here you go, this apple is yours.

We both know what happened there. I had one apple and I gave it to you.

You now have one apple and I have none.

Apple2

However, what if we’re now sitting at our computers and I give you an electronic apple.  Here you go, again it’s yours.

Now you probably have a few questions like ‘What the hell is a digital apple?’  Let’s ignore that one for a minute.

You may also be thinking  ‘How do I know he didn’t keep a copy of that apple?’  ‘Did he also email my apple to a million other people?’  ‘How do I know that apple is mine and mine alone?’

Maybe you’re just thinking  ‘All this talk of apples is making me hungry’.

Regardless, from the above it should be clear that a transaction between us in the real world (apple) is easy while a transaction between us in the electronic world (electronic apple) is complicated.

In the electronic world we need some sort of record of who owns what.

Think of Al Capone’s bookkeeper in the movie The Untouchables who knew everything about Capone’s transactions.  We could hire him to keep a record of who owns what electronic apples between us.  However, he could be tempted to add a couple of electronic apples to his own personal account now and then and who would trust him anyway?  He works for a world famous gangster, plus he’s long dead, but we digress.

The Blockchain solution is to give everyone the set of records.

Instead of one person controlling it, everyone has a copy of the records on their computer.  If we exchange our apples our records won’t synchronise until we both agree what happened.  If I cheat and keep a copy it won’t synchronise. If you extrapolate that out to everyone, it becomes very hard to cheat when everyone has a record to check transactions against.  Swap apples for Bitcoins or any other electronic transaction and that’s Blockchain explained via apples and gangsters.