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BlockChains &�Elliptic Curve Cryptography �

Presented by: Kelle Clark�Mini Talk Series�04/08/21

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A Blockchain is a decentralized,�distributed,�immutable ledger that can be extended by all member nodes within its consortium network.�

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Blockchains

Three types of accounts shown as the nodes: user accounts, member accounts and smart contract account.

Consortium network of member nodes uses a Peer-to-Peer (P2P) Architecture �

DB of blocks is replicated at all member nodes

Consortium Method chosen governs the creation of the blocks�

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Base case (index 0):�Genesis block 🡪 sha-256 🡪encrypt��Inductive step (prev block added):�next transaction(s)+ metadata + prev block’s hash 🡪 sha-256 🡪 mine block to “satisfy difficulty level” with elliptic curve encryption��== immutable ledger��

Overview of a Blockchain Construction

time

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Blockchains�post 2009 �Choose the platform

Bitcoin

Ethereum

Hyperledger�Fabric

IBM Blockchain

Microsoft Azure VSCode�BC extension

Litecoin

PUBLIC

PRIVATE

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Consortium Method needs to provide incentive to use assets for good not to attack!

Tamper Evident through cryptographic links, immutable blocks

Earning the right to create, creates a reward system that generates electronic currency…like Bitcoin and Ether

Trustless, no need for parties involved to trust each other

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Decide on the consortium method:�how to earn the reward.�

POW

POS

PoST�dPoS

dPoW

POA

Etc.

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Finding the needle in a Blockchain

Access a block by the hash value or index in chain, but no common blockchain query language.

Within Etherium, can use �Etherium Quey Language EQL patterned after SQL��

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SELECT block.parent.number, block.hash, block.timestamp, block.number, block.amountOfTransactions

FROM ethereum.blocks AS block

WHERE block.timestamp �BETWEEN date('2016−01−01') AND now() �AND block.transactions.size >10

ORDER BY block.transactions.size

LIMIT 100

Reference : Bragagnolo et al.

EQL Block Query Example

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The Graph and Bitquery

To access the data stored within blocks of a blockchain, developers of dApps using blockchain db depend on centralized servers to index the data….defeating the beauty of Blockchain��The Graph ~ perform queries on Etherium

Bitquery ~ > performs queries on 20 blockchain platforms�

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Creating a BlockChain in Visual Studio Code using js

Download Visual Studios Code.�Git clone Savjee/SavjeeCoin: A simple blockchain in Javascript. For educational purposes only. (github.com)�In VSCode, open node_modules/savjee/src/blockchain.js��add lines to end of blockcoin.js:�const myKey = ec.genKeyPair();�const {Blockchain2, Transaction2} = require('savjeecoin’);�const myChain = new Blockchain();�const tx = new Transaction(myKey.getPublic('hex'), 'toAddress', 100);�tx.signTransaction(myKey);�myChain.addTransaction(tx);�myChain.minePendingTransactions(myKey.getPublic('hex'));

console.log(JSON.stringify(myChain, null, 4));�console.log('Public key:', myKey.getPublic('hex’));�console.log('Private key:', myKey.getPrivate('hex’));��in terminal run cli: node blockchain.js

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Resources

An overview of Elliptic Curve Digital Signature Algorithm and the elliptic curve used by Bitcoin Elliptic Curve Arithmetic and Bitcoin | Nathan Dalaklis – YouTube
EQL: Bragagnolo, Santiago et al. “Ethereum Query Language.” 2018 IEEE/ACM 1st International Workshop on Emerging Trends in Software Engineering for Blockchain (WETSEB) (2018): 1-8.
A summary consortium methods: Crypto-Corner Blog on Crypto Jargon: POW, POS, POA, ... Explained
Tutorial for building a Blockchain using Elliptic Curve in VS Code! Savjee/SavjeeCoin: A simple blockchain in Javascript. For educational purposes only. (github.com)
Distributed Ledgers in IIoT (iiconsortium.org)
Secp256k1 - Bitcoin Wiki
Practical Cryptography for Developers (nakov.com) https://cryptobook.nakov.com/digital-signatures/ecdsa-sign-verify-messages
Introduction to smart contracts | ethereum.org

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Databases: systems to record and access data for functional or analytic tasks.

SQL and NoSQL types of DB
Traditional databases use a Client Server Architecture where trust rests in the management of the system.

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Centralized: single point of failure/authority

Decentralized:�Division

Distributed:�Independence

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Proof-of-Work�(POW)�

The difficulty level of the cryptographic hashing problem tied to the collective computing power of the network and needed transactions per second.
Expense of MINING (working to solve THE problem) forms a basis for the value of the cryptocurrency

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Proof-of-Stake�(POS)�

POS rewards miners for holding on to and using e-currency earned (staking)
Dividends earned are a function of amount staked
Collaborative computation to solve problem lessens energy consumption and manages deflation (amt of assets on market).