abcd of blockchain

1. DISCOVER . LEARN . EMPOWER
University Institute of Engineering
DEPARTMENT OF COMPUTER
SCIENCE & ENGINEERING
Bachelor of Engineering (Computer Science &
Engineering)
Value Added Course-Blockchain Essentials and
Development of DApps
DAY 1
Prepared By :Er. Jaideep Kaur(E12885)

2. 1.2
Introduction to Blockchain

3. 1.3
BLOCKCHAIN DEFINED
• A blockchain is a type of distributed ledger technology (DLT) that consists of growing lists
of records, called blocks, that are securely linked together using cryptography.
• Each block contains a cryptographic hash of the previous block, a timestamp, and transaction
data (generally represented as a Merkle tree).
• The timestamp proves that the transaction data existed when the block was created.
• Since each block contains information about the previous block, they effectively form a chain ,
with each additional block linking to the ones before it.
• Consequently, blockchain transactions are irreversible in that, once they are recorded, the data
in any given block cannot be altered retroactively without altering all subsequent blocks.

4. 1.4
BLOCKCHAIN= DISTRIBUTED LEDGER +
COMPUTATIONAL POWER + CRYPTOGRAPHIC HASH

5. 1.5
Ledger- Collection of Transactions in the form of Blocks
A Visual Representation of Blockchain ledger on a single Peer node in a network

6. 1.6
Distributed Ledger- Each Peer node shares a copy of the ledger
A Visual Representation of Blockchain ledger on multiple Peer nodes in a network
Peer A
Peer C
Peer B
Peer D

7. 1.7
Cryptographic Hash
• Cryptographic Hash is a Hash function that takes random size input and yields a fixed-size output.
• Hash is also called Message Digest or Digital Fingerprint.
• It is one-way function. i.e. it cannot be reversed.
• In Blockchain, a 256 byte Hash is generated.
256 byte hash

8. 1.8
Computational Power – Consensus Algorithm
• A consensus algorithm is a procedure through which all the peers of the Blockchain
network reach a common agreement about the present state of the distributed ledger.
• In this way, consensus algorithms achieve reliability in the Blockchain network and
establish trust between unknown peers in a distributed computing environment
• Few Consensus Algorithms include:
1. Proof of work (PoW)
2. Proof of Stake (PoS)
3. Practical Byzantine Fault Tolerance (PBFT)

9. 1.9
Blockchain (contd)..
• A blockchain was created by a person (or group of people) using the name
(or pseudonym) Satoshi Nakamoto in 2008 to serve as the public distributed
ledger for bitcoin cryptocurrency transactions.
• The implementation of the blockchain within bitcoin made it the first digital currency
to solve the double-spending problem without the need of a trusted authority or
central server.

10. 1.10
Centralized vs Distributed vs Decentralized Systems

11. 1.11
Centralized vs Decentralized Systems

12. 1.12
Centralized vs Decentralized Systems (contd..)

13. 1.13
Benefits of Blockchain

14. 1.14
References
• https://en.wikipedia.org/wiki/Blockchain#:~:text=A%20blockchain%20is%20a%20ty
pe,securely%20linked%20together%20using%20cryptography.