Blockchain technology involves a distributed ledger of encrypted blocks of data that are chained together. Each block contains a cryptographic hash of the previous block, transaction data, and a proof-of-work. The blockchain is shared across a peer-to-peer network, and nodes in the network must reach a consensus on the validity of new blocks added to the chain through a proof-of-work mechanism to prevent tampering with transaction records. Some applications of blockchain technology include Bitcoin and other cryptocurrencies, as well as use cases for supply chain management, digital identity, and financial transactions.

1. BLOCKCHAIN
TECHNOLOGY
DONE BY:
RAJLAKSHMI MAURYA
15261A05G6
CSE-3

2. CONTENTS
 Introduction
 History
 Features
 Understanding Blocks in Blockchain
 Proof of Work
 P2P Network
 Working
 Application

3. Introduction to Block chain
 Chain of blocks that contain information
 Block contains data in form of coding
 Block chain is
 Distributed ledger
 Completely open to anyone
 Stored data is difficult to change

4. History
 Proposed in 1991
 Originally intended to timestamp digital
documents
 Adopted by Satoshi Nakomoto (pseudonym)
in 2009 to create digital currency
(Bitcoin)

5. Features

8. Contents of a Block
 Data
 Example: bitcoins – details of sender, receiver,
amount of bitcoin
 Hash
 Identifies block
and its content
 Useful in
detecting changes

9.  Hash of previous block

10.  What happens when data of block is
tampered?
 Rest of blocks will be invalidated
 But using hashes enough can not prevent tampering
 to overcome the drawbacks of hashes we use “proof
of work”

11. Proof of Work
 Creating the proof of work protocol for achieving
consensus between devices on a distributed network
 Mechanism that slows creation of new block
 Example: in case of bitcoin
 Hence security of block chain comes from hashing
and proof of work

12. P2P Network
 Blockchain secure themselves by being
distributed.
 Uses P2P network
 Each participants (nodes) get
full copy of blockchain
 new block is verified
by each node of
p2p network to ensure
its not tampered
P2P
New block

13. Consensus
 All the nodes in network
create consensus to verify
valid and invalid blocks
 Blocks that are tampered
will be rejected
 So in order to successfully
tamper with blockchain
 redo proof of work for each
block and
 take control of more than
50% p2p nodes

14. Advantages
 Process Integrity
 made in such a way that any block or even a
transaction that adds to the chain cannot be
tampered
 Traceability
 trace out any existing problem
 Security
 Highly secure due to provide unique id (hash value)
 Faster processing
 Before , the overall banking process takes around three
days to settle but after the introduction of Blockchain,
the time reduced to nearly minutes or even seconds.

15. Disadvantages
 Power Use
◦ Keeping a real-time ledger is one of the reasons for
this consumption because every time it creates a new
node, it communicates with each and every other node
at the same time.
 Cost
◦ More cost due to energy consumption
 Uncertain regulatory status
◦ a hurdle for Bitcoin to get accepted by the preexisting
financial institutions.

16. Applications
 Bitcoin –digital cash works on block
chain
 Blockchain Implementation

18. Some other Applications

19. References
 https://blockgeeks.com/guides/what-is-
blockchaintechnology/#How_Does_Blockchain
_Work
 https://data-flair.training/blogs/features-of-
blockchain/
 https://www.coindesk.com/information/what-is-
blockchain-technology
 what is block chain -ieee paper
https://ieeexplore.ieee.org/document/8024092

20. Thank you!