7.Distributed Ledgers: The Evolution of Distributed Ledgers
Channel: Rafiq Bouhsen
Date: 2021-06-02

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Source:
EDX
LinuxFoundationX LFS170x
Blockchain: Understanding Its Uses and Implications
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A) Island of Yap: An Example
Let's review an example on Yap Island:
Alice agrees to trade Bob her stone by the pond in exchange for all of
his cattle.
Alice and Bob announce their transaction to the tribe.
Everyone updates their mental ledger.
From this point on, they agree that the stone by the pond is owned
by Bob.

B) Island of Yap: Corruption Is Near Impossible
Alice tries to corrupt Carol, so that Carol’s ledger shows that Alice never gave up ownership of the stone.

1)Centralized ledger: 
Only one place to cheat.
2)Decentralized ledger:
Carol will be outvoted by the rest of the tribe, and her version of the ledger will not be accepted.

If Alice wants to cheat, she will need a way to convince 51% or more of the tribe to accept an alternative ledger.