Block_Chain_IX.pptx

Block Chain Technology Dr. Tamal Mondal Lecture IX Symbiosis International (Deemed University) Session Objectives By the end of this session, you will be able to:  Distributed Consensus in Bitcoin – Understand the consensus mechanism Bitcoin for addition of new Blocks and...

Block Chain Technology Dr. Tamal Mondal Lecture IX Symbiosis International (Deemed University) Session Objectives By the end of this session, you will be able to:  Distributed Consensus in Bitcoin – Understand the consensus mechanism Bitcoin for addition of new Blocks and Proof of Work in detail. Traditional Consensus Traditional Consensus  Various Faults in Distributed Systems  Crash Fault  Network or Partition Faults  Byzantine Faults Bitcoin Consensus - Requirement Bitcoin Consensus - Requirement Bitcoin Consensus - Requirement Bitcoin Consensus - Requirement Bitcoin Consensus  Bitcoin Consensus Consensus Procedure in Bitcoin:  Objective: Which block to include next??  Every miner may not propose the identical block.  Challenge: Miners do not know each other.  Possible Solution: Broadcast the  Bitcoin Consensus Consensus Procedure in Bitcoin:  Observations:  Any valid block can be accepted even if it’s coming from one miner.  The protocol can work in rounds: Broadcast the accepted block to the peers and collect the next set of transactions.  Bitcoin Consensus Consensus Procedure in Bitcoin:  Solution:  Every miner tries solve a challenge posed by the network.  The block accepted for the miner who can prove first that the challenge has been solved.  Bitcoin Consensus Consensus Procedure in Bitcoin: Bitcoin Consensus  Simplified Consensus Algorithm for Bitcoin Bitcoin Consensus  Double Spending Attack Bitcoin Consensus  Double Spending Attack – Solution (6 Confirmations) Bitcoin Consensus  Double Spending Attack – Solution (6 Confirmations) Bitcoin Consensus  Incentives and Proof of Work Bitcoin Consensus  Incentives and Proof of Work Incentive I : Block Reward Bitcoin Consensus  Incentives and Proof of Work Incentive 2 : Transaction Fees Bitcoin Consensus  Proof of Work Other Problems to Solve: Bitcoin Consensus  Proof of Work Bitcoin Consensus  Proof of Work Avoids Sybil Attack Bitcoin Consensus  Proof of Work  Hash (r|x) = y, here Hash(nonce|| Prev_Hash|| tx….tx)