blockchain

1. IntroductionToBlockchain

2. WhatisBlockchain?
Blockchain is simply a data structure where each block is linked to another block
in a time- stamped chronological order
It is a distributed digital ledger of an immutable public record of digital
transactions.
Every new record is validated across the distributed network before it is stored
in a block.
Each block is identified by its cryptographic signature.
The first block of the blockchain is known as Genesis block

4. PublicLedger
• Records all transactions across business network
• Shared between participants
• Participants have own copy through replication
• Permissioned, so participants see only appropriate transactions
• It is the shared system of record.
Shared Ledger

5. Blockchain as public ledger
Distributed ledgers are held, reorganized, and
controlled by individuals called nodes.
The database is constructed independently by
each node.
Every transaction occurring on the network is
processed, and a conclusion on the development of
the database is created by each node.
Based on the transaction, voting is carried out on
the changes completed on the database.
How Distributed Ledgers Work

6. BlockInBlockchain
A block in a blockchain is a digital file that stores transaction data and links to other blocks.
Blocks are the fundamental unit of a blockchain, and they are linked together to form a chain
What's in a block?
Header: Contains a timestamp, the hash of the previous block, and other
metadata
Data: Contains the actual information, such as transactions and smart
contracts
Hash: A unique cryptographic value that represents the entire block

7. Howdoblockswork?
New transactions are processed and bundled into a block
The network validates the transactions
The block is sealed and linked to previous blocks
The chain is immutable, meaning the contents of each block cannot be altered without
affecting the others

8. Blockchain transaction is nothing more than data transmission across a blockchain
system’s network of computers.
A blockchain network of computers stores transactional data as replicas, with the storage,
commonly referred to as a digital ledger
The block includes a batch of transactions and has time and size constraints on how many
transactions it can hold.
When the block timer expires, or the maximum number of transactions is reached, the
block is added to the chain, and the next block iteration begins.
Blockchain technology uses peer-to-peer (P2P) networks to create a shared and secure
ledger in which transactions are recorded as immutable time-stamped digital blocks.
Blockchain transaction

9. The Chain
Chain is a fundamental component of
blockchain technology, serving as the
backbone of decentralized systems.
It is a sequence of blocks, each containing
a list of transactions.
These blocks are linked linearly
chronologically, forming a chain.

10. The longest chain rule in blockchain is a rule
that states that new blocks are added to the
longest branch of a blockchain.
This rule ensures that all nodes on a network
agree on the same transaction history.
The longest chain rule ensures that all nodes
on a network agree on the same transaction
history.
The longest chain rule allows computers
acting independently over a network to
maintain the same view of a globally updated
file.
The longest chain

11. Permissioned Model of Blockchain
Permissioned blockchains allow for
selective data visibility, ensuring that the
information is only accessible to only
authorized participants.
This feature is highly valuable in healthcare
and finance industries, where data privacy
is paramount.

13. Cryptographic
Cryptography is a way of securing
data against unauthorized access.
In the blockchain, cryptography is
used to secure transactions between
two nodes in the blockchain network.
As mentioned above, there are two
main concepts in blockchain –
cryptography and hashing.

14. A hash function turns an input (for example
text) into a string of bytes with a fixed length
and structure.
The output or value created is called a 'hash
value' or 'checksum. '
Any hash value created from data using a
specific hashing algorithm is always the same
length and one-way - it cannot be reversed.
Hash Function

15. Determinism
Fixed output size
Efficiency
Uniformity
Pre-image resistance
Collision resistance
Properties Of Hash Function

16. A hash pointer is a data structure that points to a block of data and includes a hash
value for that block.
Hash pointers are used in blockchain technology to ensure that data is immutable,
meaning it cannot be altered or tampered with.
A hash function converts the data in a block into a hash value.
A hash pointer contains the hash value and a pointer to the block.
If the block is modified, the hash value will change.
Hash pointers can be used to validate that the block has not been modified.
Hash Pointer
How it works

17. Merkle Tree
Merkle tree also known as hash tree is a
data structure used for data verification
and synchronization.
It is a tree data structure where each
non-leaf node is a hash of it’s child
nodes.
All the leaf nodes are at the same depth
and are as far left as possible.
It maintains data integrity and uses hash
functions for this purpose.

18. This is a binary merkel tree, the top hash is a hash of the entire tree.
This structure of the tree allows efficient mapping of huge data and
small changes made to the data can be easily identified.
If we want to know where data change has occurred then we can
check if data is consistent with root hash and we will not have to
traverse the whole structure but only a small part of the structure.
The root hash is used as the fingerprint for the entire data.

19. Merkle trees are useful in distributed systems where same data should
exist in multiple places.
Merkle trees can be used to check inconsistencies.
Apache Cassandra uses Merkle trees to detect inconsistencies between
replicas of entire databases.
It is used in bitcoin and blockchain.
Applications:

20. THANK YOU