SlideShare una empresa de Scribd logo
1 de 20
Descargar para leer sin conexión
BLOCK CHAIN AND BITCOIN
TEJHASKAR ASHOK KUMAR
VIGNESHWAR RAMASWAMY
What is blockchain?
◦ Blockchain is a decentralized, distributed back-end database that
maintains a distributed-ledger that is used to record transactions
across many computers. The main advantage of blockchain is any
record cannot be altered easily without changing the sub-sequent
blocks.
◦ A blockchain is a ledger of transactions replicated across several
computers connected to a peer-to-peer network.
◦ Blockchain has several applications in the field of crypto-currency,
banking, supply chain, healthcare, voting etc.
◦ Game theory, software Engineering and cryptography science are the
fields involved in blockchain.
Approaches to achieve consensus:
◦ As the blockchain are distributed systems, every node has exact same authority. So any node can easily
modify data or mislead the communication between the nodes while doing a transaction.
◦ It causes a distributed network security problem
◦ Problem : achieving consensus in a distributed network with potentially faulty nodes
◦ Approaches to Consensus/ Byzantine Fault Tolerance:
✓State Machine Replication : Leslie Lamport’s Consensus
✓Proof-Of-Work : Nakomoto’s Consensus
State machine replication approach
◦ State Machine Replication is a general approach for implementing a fault-tolerant system by replicating
servers and coordinating client interactions with server replicas.
◦ Technique for implementing fault-tolerant service in terms of a state machine:
➢Place copies of the state machine on multiple, independent servers
➢Receive client requests as input to the state machine.
➢Choose an ordering for the inputs.
➢Execute the inputs in the chosen order on each servers.
➢Respond to clients with the output form the state machine.
How blockchain works?
◦ Blockchain is a distributed ledger which is
accessible to anyone. Once a data has been
recorded to a blockchain, it becomes very
difficult to change it.
◦ Every block in the blockchain has the
following elements:
◦ Data
◦ Hash
◦ Hash of the previous block
How blockchain works?
◦ This is a chain of 3 blocks. Each block has a hash and hash of the
previous block.
◦ First block is genesis block as it does not point to any block.
◦ If the data in the block 2 is tampered, the hash value is changed.
So, the block 3 and all following blocks are invalid as it no longer
stores a valid hash.
◦ This technique effectively makes the blockchain so secure.
Proof of Work:
◦ Proof of work is a protocol that has the main goal
of deterring cyber-attacks such as a distributed denial-of-
service attack (DDoS) which has the purpose of exhausting the
resources of a computer system by sending multiple fake
requests.
◦ In blockchain, PoW is a mathematical puzzle known as nonce
which has to be solved to create a new block.
◦ This nonce ensures all the transactions in the block are valid
and verified.
◦ Blockchain uses merkle-tree based proof-of-work function.
Merkle-tree (hash tree):
◦ In cryptography, merkle-tree is a tree in which every leaf node
is labelled with the cryptographic hash of a data block and
every non-leaf node is labelled with the cryptographic hash in
the label of its child nodes.
◦ Each transaction in the set that makes up a block is fed through
a program that creates an encrypted code known as the hash
value.
◦ Hash values are further combined in a system known as
merkle-tree
Merkle-tree (Hash tree):
◦ Computer A sends a hash of the file to computer B.
◦ Computer B checks that hash against the root of the Merkle
tree.
◦ If there is no difference, we're done! Otherwise, go to step 4.
◦ If there is a difference in a single hash, computer B will request
the roots of the two subtrees of that hash.
◦ Computer A creates the necessary hashes and sends them back
to computer B.
◦ Repeat steps 4 and 5 until you've found the data blocks(s) that
are inconsistent. It's possible to find more than one data block
that is wrong because there might be more than one error in
the data.
Blockchain implementation
– python:
◦ This is a simple implementation of a block
using python.
◦ A chain of block can be implemented by
using python Lists.
◦ The hash of the current block acts as a
pointer to the previous block.
◦ From this, it is clear that the blockchain
uses linked-list data structure.
BITCOIN-INTRODUCTION
◦ What is Bitcoin?
◦ Bitcoin is a Crypto-Currency
◦ Bitcoin is the First Decentralized digital currency.
◦ Transactions takes place between users directly using cryptography.
◦ These transactions are verified by network nodes and they are
recorded in a public distributed ledger called block chain.
◦ Who invented this technology?
◦ A software developer, Satoshi nakamoto proposed bitcoin.
CRYPTOGRAPHY
◦ Public key cryptography ( Asymmetric cryptography)
◦ A cryptographic system that uses two pairs of keys
◦ Public keys – distributed widely
◦ Private keys - known only to the owner
◦ How the keys are generated?
◦ Depends on cryptographic algorithms which are based on mathematical problems to produce one-way
functions
ECDSA - Elliptic Curve Digital Signature Algorithm
◦ In bit coin,
◦ Private key is a randomly generated number.
◦ Private key is a single unsigned 256-bit integer (32 bytes).
◦ Public key is a number that corresponds to private key.
◦ Public key can be calculated from private key, but not vice versa.
◦ Compressed public keys are 33 bytes
◦ Prefix - 0x02 or 0x03
◦ X – 256-bit integer.
ECDSA - Elliptic Curve Digital Signature
Algorithm
◦ Uncompressed keys are 65 bytes
◦ Prefix – 0x04
◦ Two 256-bit integer values called x and y.
◦ Prefix of the compressed public key allows for the y value to be derived from the x value.
Digital Signature:
◦ A cryptographic value that is calculated from the data and secret key known only by the signer.
◦ A number that proves that a signing operation took place.
◦ A signature is mathematically generated from a hash of something to be signed, plus a private key.
◦ Resulting signatures are either 73, 72, or 71 bytes long.
Process
CREATE A
TRANSACTION.
ATTACH RECEIVERS
PUBLIC KEY TO THIS
AMOUNT OF COINS.
SIGN IT WITH
SENDER'S PRIVATE
KEY.
THEN, THIS
TRANSACTION IS
BROADCASTED TO
THE BITCOIN
NETWORK.
THE COMPLETE
HISTORY OF
TRANSACTIONS IS
KEPT BY EVERYONE,
SO ANYONE CAN
VERIFY WHO IS THE
CURRENT OWNER OF
ANY GROUP OF
COINS.
THIS COMPLETE
RECORD OF
TRANSACTIONS IS
KEPT IN THE BLOCK
CHAIN.
HASHCASH
◦ Bitcoin uses the hashcash Proof of work function as the mining core.
◦ Hashcash function makes generating bitcoins more difficult
◦ The bitcoin miners make their effort in creating hashcash proof of work function to produce a new
block in the block chain.
◦ Hashcash uses hash functions as a building block.
◦ Hashcash uses symmetric key cryptography, namely a one-way hashcash function.
◦ In bitcoin, block-chaining, and the hashcash cost-function all use SHA256 as the
underlying cryptographic hash function.
BITCOIN MINING
◦ Mining is a process of adding transaction records to Bitcoin public ledger of past transactions.
◦ Adding a block to the block chain is difficult, which requires time and processing power.
◦ The miner to put forth this time and electricity is the one who manages to produce the block and
gets a reward.
◦ The block producer gets a bounty of some number of bitcoins, which is agreed-upon by the network.
◦ The network rules are such that the difficulty is adjusted to keep block production to approximately 1
block per 10 minutes.
Double spending problem
◦ A double spend is an attack where the given set of coins is spent in
more than one transaction.
◦ Send two conflicting transactions in rapid succession into the Bitcoin
network. This is called a race attack.
◦ When digital currencies are copied, it becomes worthless.
How to deal with this problem?
◦ Bitcoin network shields from the activity of double spending.
◦ It verifies and records each transactions within the block chain.
◦ Block chain maintains a record of all the transactions made using bit
coins by miners.
◦ The ledger system in the block chain ensures that the transactions are
confirmed by miners.
References:
◦ [1] Blockchain - https://en.wikipedia.org/wiki/Blockchain
◦ [2] State Machine Replication - https://en.wikipedia.org/wiki/Blockchain
◦ [3] Merkle Tree - https://en.wikipedia.org/wiki/Merkle_tree
◦ [4] “Bitcoin : A peer-to-peer Electronic Cash System”, Satoshi Nakamoto, October 31, 2008
◦ [5] Cryptography - https://en.bitcoin.it/wiki/How_bitcoin_works
◦ [6] ECDSA - https://en.bitcoin.it/wiki/Elliptic_Curve_Digital_Signature_Algorithm
◦ [7] HashCash - https://en.wikipedia.org/wiki/Hashcash
◦ [8] Bitcoin Mining - https://en.bitcoin.it/wiki/Mining
◦ [9] Double spending - https://www.investopedia.com/ask/answers/061915/how-does-block-chain-prevent-doublespending-bitcoins.asp
◦Thank you !

Más contenido relacionado

La actualidad más candente

Bitcoin - Beyond the basics
Bitcoin - Beyond the basicsBitcoin - Beyond the basics
Bitcoin - Beyond the basicsChris DeRose
 
What to expect from Blockchain in 2019?
What to expect from Blockchain in 2019?What to expect from Blockchain in 2019?
What to expect from Blockchain in 2019?PECB
 
Intro to Blockchain - And, by the way, what the heck is proof-of-work?
Intro to Blockchain - And, by the way, what the heck is proof-of-work?Intro to Blockchain - And, by the way, what the heck is proof-of-work?
Intro to Blockchain - And, by the way, what the heck is proof-of-work?Jim Flynn
 
Abhishek jaiswal blockchain
Abhishek jaiswal blockchainAbhishek jaiswal blockchain
Abhishek jaiswal blockchainAbhishek Jaiswal
 
Blockchain technology
Blockchain technologyBlockchain technology
Blockchain technologyAayt Bahaa
 
BitCoin explained
BitCoin explainedBitCoin explained
BitCoin explainedHarelc
 
Anatomy of a blockchain
Anatomy of a blockchainAnatomy of a blockchain
Anatomy of a blockchainAvtar Sehra
 
Introduction to Blockchain
Introduction to BlockchainIntroduction to Blockchain
Introduction to Blockchainsubbul
 
Introduction to Blockchain
Introduction to BlockchainIntroduction to Blockchain
Introduction to BlockchainSanjeev Mishra
 
Blockchain Technology
Blockchain TechnologyBlockchain Technology
Blockchain TechnologyNimmy Solomon
 
Introduction to Blockchain
Introduction to BlockchainIntroduction to Blockchain
Introduction to BlockchainAkshay Kumar
 
Bitcoin and Blockchain
Bitcoin and BlockchainBitcoin and Blockchain
Bitcoin and BlockchainChen Wu
 
Introduction to Blockchain Development
Introduction to Blockchain DevelopmentIntroduction to Blockchain Development
Introduction to Blockchain DevelopmentLightstreams
 
Blockchain, cryptography and tokens — NYC Bar presentation
Blockchain, cryptography and tokens — NYC Bar presentationBlockchain, cryptography and tokens — NYC Bar presentation
Blockchain, cryptography and tokens — NYC Bar presentationPaperchain
 

La actualidad más candente (20)

Bitcoin - Beyond the basics
Bitcoin - Beyond the basicsBitcoin - Beyond the basics
Bitcoin - Beyond the basics
 
BitCoin Protocol
BitCoin ProtocolBitCoin Protocol
BitCoin Protocol
 
What to expect from Blockchain in 2019?
What to expect from Blockchain in 2019?What to expect from Blockchain in 2019?
What to expect from Blockchain in 2019?
 
Blockchain Technology
Blockchain TechnologyBlockchain Technology
Blockchain Technology
 
Intro to Blockchain - And, by the way, what the heck is proof-of-work?
Intro to Blockchain - And, by the way, what the heck is proof-of-work?Intro to Blockchain - And, by the way, what the heck is proof-of-work?
Intro to Blockchain - And, by the way, what the heck is proof-of-work?
 
Abhishek jaiswal blockchain
Abhishek jaiswal blockchainAbhishek jaiswal blockchain
Abhishek jaiswal blockchain
 
Blockchain technology
Blockchain technologyBlockchain technology
Blockchain technology
 
BitCoin explained
BitCoin explainedBitCoin explained
BitCoin explained
 
Blockchain
BlockchainBlockchain
Blockchain
 
Anatomy of a blockchain
Anatomy of a blockchainAnatomy of a blockchain
Anatomy of a blockchain
 
Blockchain
BlockchainBlockchain
Blockchain
 
Introduction to Blockchain
Introduction to BlockchainIntroduction to Blockchain
Introduction to Blockchain
 
Introduction to Blockchain
Introduction to BlockchainIntroduction to Blockchain
Introduction to Blockchain
 
Blockchain Technology
Blockchain TechnologyBlockchain Technology
Blockchain Technology
 
Introduction to Blockchain
Introduction to BlockchainIntroduction to Blockchain
Introduction to Blockchain
 
Bitcoins Math
Bitcoins MathBitcoins Math
Bitcoins Math
 
Bitcoin and Blockchain
Bitcoin and BlockchainBitcoin and Blockchain
Bitcoin and Blockchain
 
Introduction to Blockchain Development
Introduction to Blockchain DevelopmentIntroduction to Blockchain Development
Introduction to Blockchain Development
 
An Introduction to Blockchains
An Introduction to BlockchainsAn Introduction to Blockchains
An Introduction to Blockchains
 
Blockchain, cryptography and tokens — NYC Bar presentation
Blockchain, cryptography and tokens — NYC Bar presentationBlockchain, cryptography and tokens — NYC Bar presentation
Blockchain, cryptography and tokens — NYC Bar presentation
 

Similar a Blockchain and bitcoin

A Quick Start To Blockchain by Seval Capraz
A Quick Start To Blockchain by Seval CaprazA Quick Start To Blockchain by Seval Capraz
A Quick Start To Blockchain by Seval CaprazSeval Çapraz
 
The Blockchain - The Technology behind Bitcoin
The Blockchain - The Technology behind Bitcoin The Blockchain - The Technology behind Bitcoin
The Blockchain - The Technology behind Bitcoin Jérôme Kehrli
 
Blockchain technology Overview
Blockchain technology OverviewBlockchain technology Overview
Blockchain technology OverviewLalitha Prasanna
 
Blockchain Fundamental_KIPMI_2022.02.26.pdf
Blockchain Fundamental_KIPMI_2022.02.26.pdfBlockchain Fundamental_KIPMI_2022.02.26.pdf
Blockchain Fundamental_KIPMI_2022.02.26.pdfadinugroho751867
 
Architecture and operations.pptx
Architecture and operations.pptxArchitecture and operations.pptx
Architecture and operations.pptxharshitmittal737363
 
Blockchain, bitcoin, ethereum and ICOs
Blockchain, bitcoin, ethereum and ICOsBlockchain, bitcoin, ethereum and ICOs
Blockchain, bitcoin, ethereum and ICOsBogdan Fiedur
 
Blockchain Technology | Bitcoin | Ethereum Coin | Cryptocurrency
Blockchain Technology | Bitcoin | Ethereum Coin | CryptocurrencyBlockchain Technology | Bitcoin | Ethereum Coin | Cryptocurrency
Blockchain Technology | Bitcoin | Ethereum Coin | CryptocurrencyUnbiased Technolab
 
Block chain technology
Block chain technologyBlock chain technology
Block chain technologyMd. Syful Azam
 
Blockchain. A Guide For Beginners
Blockchain. A Guide For BeginnersBlockchain. A Guide For Beginners
Blockchain. A Guide For BeginnersElifTech
 
Blockchain 101 - public, tokenized blockchains
Blockchain 101 - public, tokenized blockchainsBlockchain 101 - public, tokenized blockchains
Blockchain 101 - public, tokenized blockchainsBrett Colbert
 
Node.js Blockchain Implementation
Node.js Blockchain ImplementationNode.js Blockchain Implementation
Node.js Blockchain ImplementationGlobalLogic Ukraine
 
Bitcoin, Banking and the Blockchain
Bitcoin, Banking and the BlockchainBitcoin, Banking and the Blockchain
Bitcoin, Banking and the Blockchainseancarmody
 
Idea To IPO Blockchain Slides
Idea To IPO Blockchain SlidesIdea To IPO Blockchain Slides
Idea To IPO Blockchain SlidesRoger Royse
 

Similar a Blockchain and bitcoin (20)

A Quick Start To Blockchain by Seval Capraz
A Quick Start To Blockchain by Seval CaprazA Quick Start To Blockchain by Seval Capraz
A Quick Start To Blockchain by Seval Capraz
 
The Blockchain - The Technology behind Bitcoin
The Blockchain - The Technology behind Bitcoin The Blockchain - The Technology behind Bitcoin
The Blockchain - The Technology behind Bitcoin
 
Day 1.pptx
Day 1.pptxDay 1.pptx
Day 1.pptx
 
Blockchain Technology
Blockchain TechnologyBlockchain Technology
Blockchain Technology
 
Blockchain technology Overview
Blockchain technology OverviewBlockchain technology Overview
Blockchain technology Overview
 
Blockchain Fundamental_KIPMI_2022.02.26.pdf
Blockchain Fundamental_KIPMI_2022.02.26.pdfBlockchain Fundamental_KIPMI_2022.02.26.pdf
Blockchain Fundamental_KIPMI_2022.02.26.pdf
 
Architecture and operations.pptx
Architecture and operations.pptxArchitecture and operations.pptx
Architecture and operations.pptx
 
Chapter 2.pptx
Chapter 2.pptxChapter 2.pptx
Chapter 2.pptx
 
Blockchain, bitcoin, ethereum and ICOs
Blockchain, bitcoin, ethereum and ICOsBlockchain, bitcoin, ethereum and ICOs
Blockchain, bitcoin, ethereum and ICOs
 
Blockchain Technology | Bitcoin | Ethereum Coin | Cryptocurrency
Blockchain Technology | Bitcoin | Ethereum Coin | CryptocurrencyBlockchain Technology | Bitcoin | Ethereum Coin | Cryptocurrency
Blockchain Technology | Bitcoin | Ethereum Coin | Cryptocurrency
 
BITCOIN EXPLAINED
BITCOIN EXPLAINEDBITCOIN EXPLAINED
BITCOIN EXPLAINED
 
Block chain technology
Block chain technologyBlock chain technology
Block chain technology
 
blockchain.pptx
blockchain.pptxblockchain.pptx
blockchain.pptx
 
Blockchain. A Guide For Beginners
Blockchain. A Guide For BeginnersBlockchain. A Guide For Beginners
Blockchain. A Guide For Beginners
 
Blockchain 101 - public, tokenized blockchains
Blockchain 101 - public, tokenized blockchainsBlockchain 101 - public, tokenized blockchains
Blockchain 101 - public, tokenized blockchains
 
Node.js Blockchain Implementation
Node.js Blockchain ImplementationNode.js Blockchain Implementation
Node.js Blockchain Implementation
 
Blockchain
BlockchainBlockchain
Blockchain
 
Blockchain
BlockchainBlockchain
Blockchain
 
Bitcoin, Banking and the Blockchain
Bitcoin, Banking and the BlockchainBitcoin, Banking and the Blockchain
Bitcoin, Banking and the Blockchain
 
Idea To IPO Blockchain Slides
Idea To IPO Blockchain SlidesIdea To IPO Blockchain Slides
Idea To IPO Blockchain Slides
 

Último

IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019IES VE
 
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...DianaGray10
 
UiPath Studio Web workshop series - Day 8
UiPath Studio Web workshop series - Day 8UiPath Studio Web workshop series - Day 8
UiPath Studio Web workshop series - Day 8DianaGray10
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-pyJamie (Taka) Wang
 
Videogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfVideogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfinfogdgmi
 
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online CollaborationCOMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online Collaborationbruanjhuli
 
Bird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemBird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemAsko Soukka
 
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostKubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostMatt Ray
 
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...Aggregage
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdfPedro Manuel
 
Building AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxBuilding AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxUdaiappa Ramachandran
 
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve DecarbonizationUsing IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve DecarbonizationIES VE
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsSeth Reyes
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPathCommunity
 
Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.YounusS2
 
Igniting Next Level Productivity with AI-Infused Data Integration Workflows
Igniting Next Level Productivity with AI-Infused Data Integration WorkflowsIgniting Next Level Productivity with AI-Infused Data Integration Workflows
Igniting Next Level Productivity with AI-Infused Data Integration WorkflowsSafe Software
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6DianaGray10
 
Comparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioComparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioChristian Posta
 
9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding TeamAdam Moalla
 

Último (20)

IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
 
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
Connector Corner: Extending LLM automation use cases with UiPath GenAI connec...
 
UiPath Studio Web workshop series - Day 8
UiPath Studio Web workshop series - Day 8UiPath Studio Web workshop series - Day 8
UiPath Studio Web workshop series - Day 8
 
201610817 - edge part1
201610817 - edge part1201610817 - edge part1
201610817 - edge part1
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-py
 
Videogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfVideogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdf
 
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online CollaborationCOMPUTER 10: Lesson 7 - File Storage and Online Collaboration
COMPUTER 10: Lesson 7 - File Storage and Online Collaboration
 
Bird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystemBird eye's view on Camunda open source ecosystem
Bird eye's view on Camunda open source ecosystem
 
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostKubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
 
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
 
Nanopower In Semiconductor Industry.pdf
Nanopower  In Semiconductor Industry.pdfNanopower  In Semiconductor Industry.pdf
Nanopower In Semiconductor Industry.pdf
 
Building AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxBuilding AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptx
 
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve DecarbonizationUsing IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
Using IESVE for Loads, Sizing and Heat Pump Modeling to Achieve Decarbonization
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and Hazards
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation Developers
 
Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.Basic Building Blocks of Internet of Things.
Basic Building Blocks of Internet of Things.
 
Igniting Next Level Productivity with AI-Infused Data Integration Workflows
Igniting Next Level Productivity with AI-Infused Data Integration WorkflowsIgniting Next Level Productivity with AI-Infused Data Integration Workflows
Igniting Next Level Productivity with AI-Infused Data Integration Workflows
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6
 
Comparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioComparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and Istio
 
9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team
 

Blockchain and bitcoin

  • 1. BLOCK CHAIN AND BITCOIN TEJHASKAR ASHOK KUMAR VIGNESHWAR RAMASWAMY
  • 2. What is blockchain? ◦ Blockchain is a decentralized, distributed back-end database that maintains a distributed-ledger that is used to record transactions across many computers. The main advantage of blockchain is any record cannot be altered easily without changing the sub-sequent blocks. ◦ A blockchain is a ledger of transactions replicated across several computers connected to a peer-to-peer network. ◦ Blockchain has several applications in the field of crypto-currency, banking, supply chain, healthcare, voting etc. ◦ Game theory, software Engineering and cryptography science are the fields involved in blockchain.
  • 3. Approaches to achieve consensus: ◦ As the blockchain are distributed systems, every node has exact same authority. So any node can easily modify data or mislead the communication between the nodes while doing a transaction. ◦ It causes a distributed network security problem ◦ Problem : achieving consensus in a distributed network with potentially faulty nodes ◦ Approaches to Consensus/ Byzantine Fault Tolerance: ✓State Machine Replication : Leslie Lamport’s Consensus ✓Proof-Of-Work : Nakomoto’s Consensus
  • 4. State machine replication approach ◦ State Machine Replication is a general approach for implementing a fault-tolerant system by replicating servers and coordinating client interactions with server replicas. ◦ Technique for implementing fault-tolerant service in terms of a state machine: ➢Place copies of the state machine on multiple, independent servers ➢Receive client requests as input to the state machine. ➢Choose an ordering for the inputs. ➢Execute the inputs in the chosen order on each servers. ➢Respond to clients with the output form the state machine.
  • 5. How blockchain works? ◦ Blockchain is a distributed ledger which is accessible to anyone. Once a data has been recorded to a blockchain, it becomes very difficult to change it. ◦ Every block in the blockchain has the following elements: ◦ Data ◦ Hash ◦ Hash of the previous block
  • 6. How blockchain works? ◦ This is a chain of 3 blocks. Each block has a hash and hash of the previous block. ◦ First block is genesis block as it does not point to any block. ◦ If the data in the block 2 is tampered, the hash value is changed. So, the block 3 and all following blocks are invalid as it no longer stores a valid hash. ◦ This technique effectively makes the blockchain so secure.
  • 7. Proof of Work: ◦ Proof of work is a protocol that has the main goal of deterring cyber-attacks such as a distributed denial-of- service attack (DDoS) which has the purpose of exhausting the resources of a computer system by sending multiple fake requests. ◦ In blockchain, PoW is a mathematical puzzle known as nonce which has to be solved to create a new block. ◦ This nonce ensures all the transactions in the block are valid and verified. ◦ Blockchain uses merkle-tree based proof-of-work function.
  • 8. Merkle-tree (hash tree): ◦ In cryptography, merkle-tree is a tree in which every leaf node is labelled with the cryptographic hash of a data block and every non-leaf node is labelled with the cryptographic hash in the label of its child nodes. ◦ Each transaction in the set that makes up a block is fed through a program that creates an encrypted code known as the hash value. ◦ Hash values are further combined in a system known as merkle-tree
  • 9. Merkle-tree (Hash tree): ◦ Computer A sends a hash of the file to computer B. ◦ Computer B checks that hash against the root of the Merkle tree. ◦ If there is no difference, we're done! Otherwise, go to step 4. ◦ If there is a difference in a single hash, computer B will request the roots of the two subtrees of that hash. ◦ Computer A creates the necessary hashes and sends them back to computer B. ◦ Repeat steps 4 and 5 until you've found the data blocks(s) that are inconsistent. It's possible to find more than one data block that is wrong because there might be more than one error in the data.
  • 10. Blockchain implementation – python: ◦ This is a simple implementation of a block using python. ◦ A chain of block can be implemented by using python Lists. ◦ The hash of the current block acts as a pointer to the previous block. ◦ From this, it is clear that the blockchain uses linked-list data structure.
  • 11. BITCOIN-INTRODUCTION ◦ What is Bitcoin? ◦ Bitcoin is a Crypto-Currency ◦ Bitcoin is the First Decentralized digital currency. ◦ Transactions takes place between users directly using cryptography. ◦ These transactions are verified by network nodes and they are recorded in a public distributed ledger called block chain. ◦ Who invented this technology? ◦ A software developer, Satoshi nakamoto proposed bitcoin.
  • 12. CRYPTOGRAPHY ◦ Public key cryptography ( Asymmetric cryptography) ◦ A cryptographic system that uses two pairs of keys ◦ Public keys – distributed widely ◦ Private keys - known only to the owner ◦ How the keys are generated? ◦ Depends on cryptographic algorithms which are based on mathematical problems to produce one-way functions
  • 13. ECDSA - Elliptic Curve Digital Signature Algorithm ◦ In bit coin, ◦ Private key is a randomly generated number. ◦ Private key is a single unsigned 256-bit integer (32 bytes). ◦ Public key is a number that corresponds to private key. ◦ Public key can be calculated from private key, but not vice versa. ◦ Compressed public keys are 33 bytes ◦ Prefix - 0x02 or 0x03 ◦ X – 256-bit integer.
  • 14. ECDSA - Elliptic Curve Digital Signature Algorithm ◦ Uncompressed keys are 65 bytes ◦ Prefix – 0x04 ◦ Two 256-bit integer values called x and y. ◦ Prefix of the compressed public key allows for the y value to be derived from the x value. Digital Signature: ◦ A cryptographic value that is calculated from the data and secret key known only by the signer. ◦ A number that proves that a signing operation took place. ◦ A signature is mathematically generated from a hash of something to be signed, plus a private key. ◦ Resulting signatures are either 73, 72, or 71 bytes long.
  • 15. Process CREATE A TRANSACTION. ATTACH RECEIVERS PUBLIC KEY TO THIS AMOUNT OF COINS. SIGN IT WITH SENDER'S PRIVATE KEY. THEN, THIS TRANSACTION IS BROADCASTED TO THE BITCOIN NETWORK. THE COMPLETE HISTORY OF TRANSACTIONS IS KEPT BY EVERYONE, SO ANYONE CAN VERIFY WHO IS THE CURRENT OWNER OF ANY GROUP OF COINS. THIS COMPLETE RECORD OF TRANSACTIONS IS KEPT IN THE BLOCK CHAIN.
  • 16. HASHCASH ◦ Bitcoin uses the hashcash Proof of work function as the mining core. ◦ Hashcash function makes generating bitcoins more difficult ◦ The bitcoin miners make their effort in creating hashcash proof of work function to produce a new block in the block chain. ◦ Hashcash uses hash functions as a building block. ◦ Hashcash uses symmetric key cryptography, namely a one-way hashcash function. ◦ In bitcoin, block-chaining, and the hashcash cost-function all use SHA256 as the underlying cryptographic hash function.
  • 17. BITCOIN MINING ◦ Mining is a process of adding transaction records to Bitcoin public ledger of past transactions. ◦ Adding a block to the block chain is difficult, which requires time and processing power. ◦ The miner to put forth this time and electricity is the one who manages to produce the block and gets a reward. ◦ The block producer gets a bounty of some number of bitcoins, which is agreed-upon by the network. ◦ The network rules are such that the difficulty is adjusted to keep block production to approximately 1 block per 10 minutes.
  • 18. Double spending problem ◦ A double spend is an attack where the given set of coins is spent in more than one transaction. ◦ Send two conflicting transactions in rapid succession into the Bitcoin network. This is called a race attack. ◦ When digital currencies are copied, it becomes worthless. How to deal with this problem? ◦ Bitcoin network shields from the activity of double spending. ◦ It verifies and records each transactions within the block chain. ◦ Block chain maintains a record of all the transactions made using bit coins by miners. ◦ The ledger system in the block chain ensures that the transactions are confirmed by miners.
  • 19. References: ◦ [1] Blockchain - https://en.wikipedia.org/wiki/Blockchain ◦ [2] State Machine Replication - https://en.wikipedia.org/wiki/Blockchain ◦ [3] Merkle Tree - https://en.wikipedia.org/wiki/Merkle_tree ◦ [4] “Bitcoin : A peer-to-peer Electronic Cash System”, Satoshi Nakamoto, October 31, 2008 ◦ [5] Cryptography - https://en.bitcoin.it/wiki/How_bitcoin_works ◦ [6] ECDSA - https://en.bitcoin.it/wiki/Elliptic_Curve_Digital_Signature_Algorithm ◦ [7] HashCash - https://en.wikipedia.org/wiki/Hashcash ◦ [8] Bitcoin Mining - https://en.bitcoin.it/wiki/Mining ◦ [9] Double spending - https://www.investopedia.com/ask/answers/061915/how-does-block-chain-prevent-doublespending-bitcoins.asp