Imagine that you and your best friend Bob are standing on a stage in an auditorium, and there are 1,000 people in the audience. In front of these 1,000 people, you hand your car keys to Bob, and Bob hands you his Rolex. You declare, “Bob, you now own my car.”
Bob declares back to you, “You now own my Rolex.” There are 1,000 witnesses who can each declare, without a doubt, that your car now belongs to Bob, and the Rolex belongs to you. If anyone in the audience later tells a conflicting account of who owns the car or the Rolex, the other 999 people will refute it. And, if you take a spare set of your keys and try to give that same car to someone else, the 1,000 audience members will confirm that Bob owns the car, as each of them witnessed the “transaction.” This is the essence of how the blockchain works.
In its most simple sense, the blockchain is a series of computers (thousands to potentially millions of them) that each keep the same record of an event or transaction in a ledger that is open to the public. Each record is encrypted, and the ledger is virtually hack-proof. Since all these computers see the same thing, they offer a consensus that the recorded event or transaction is valid. The most important value of the blockchain is that it allows two or more parties to interact with, say, a financial transaction, with no middleman.
https://bitcointalk.org//medium.com/@LeaxFoundation/blockchain-and-real-estate-will-it-work-e6d5eb85570c
