BITCOIN is a type of cryptocurrency. It uses BLOCKCHAIN or the so-called WORLD WIDE LEDGER. The world wide ledger is a comprehensive list of BITCOIN transactions. As I said before, money is just a settlement. The world wide ledger is like a general agreement.
Peer to peer the process for using it. That means no one in the middle. It is open source and no one controls it. When you trade with BITCOIN like passing and receiving bitcoin the list changes to a world wide ledger. Example of this when you pass a BITCOIN to your friend. In the ledger it will increase the value of BITCOIN because he received it and in your ledger will decrease the BITCOIN because you sent it. But it's not just your ledger that is affected. Because of all the thousands of ledgers around the world your transaction is also listed. I mean my ledger will see your friend increase and I will see you decrease as well. That is called DECENTRALIZATION. If there is a decrypted record such as adding a bitcoin number to its ledger it will not be accepted as it will be shown to the other thousands of ledgers that he does not have the bitcoin number he declares. That's how bitcoin is solved. It's impossible to fake it. Beauty is still Limited Supply and is now increasing in number of Users called Demand. So Value rises.