Blockchain is a distributed ledger of records called blocks that are linked using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data. Blockchain provides an open, decentralized database for transferring assets like money without a central authority. Transactions are verified through consensus mechanisms and validated before being added to the permanent blockchain in a process called mining. This makes the data auditable and resistant to modification, providing transparency and security.

1. BLOCK CHAIN
By: Tina Gupta

2. What is?
 List of Records, called Blocks
 Linked and secured using Cryptography
 Contains: has pointer to previous block, a
timestamp and transaction data
 Resistant to modification of data

3. What it does?
 Provides Open, Decentralized database
 Transfers money without any centralized
authority
 Faster money transfer
 Cheaper than third party money exchange
 Makes data transfers Auditable and
Transparent

4. Components
 Digital Ledger
 A continually updated, network hosted
‘Database’ of all transactions
 Consensus Mechanisms
 Programmed into each blockchain protocol, and
responsible for verifying and updating
transactions in ledger

5. Components
 Digital Asset
 A good transacted on blockchain, e.g
Cryptocurrency
 Network Participants
 Computed nodes with access to blockchain,
able to manipulate ledger and view
transactions.

6. How It Work?
 1. Transaction
Two parties exchange data, like money, medical
record etc.

7. How It Works?
 2. VERIFICATION
Depending upon network’s parameters, the
transaction is either verified instantly or
transcribed into a secured record and placed in
queue of pending transactions.

8. How It Works?
 3. STRUCTURE
Each block creates a 256-bit number, called
hash using network based algorithms.
A block contains : A Header, A reference to
previous block’s hash and Transaction Data.

9. How It Works?
 4. VALIDATION
Block must be validated to be added to Block
Chain.
Most acceptable validations is “Proof of Work –
The solution to a mathematical puzzle derived
from block’s header”.

10. How It Works?
 5. MINING
Miners try to “solve” the block by making
incremental changes to one variable until
solution satisfies a network-wide target.

11. How It Works?
 6. THE CHAIN
Once block is validated, Miners are rewarded
and block is distributed through the network.
Each node adds the block to the majority chain,
the network’s immutable and auditable
blockchain.

12. How It Works?
 7. BUILT IN DEFENSE
If a malicious miner tries to submit an altered
block to chain, hash function of that block and
all other blocks, would change.
The other nodes would detect the changes and
reject the block from the chain.

13. USE CASES

14. Disadvantages
 Lack of awareness
 Easy to lose, No mechanism to recover lost
bitcoins
 Untracable – this attracts crime.

15. THANKS !!!