Introduction to Blockchain Technologies held at CodeDoor.org event.

1. INTRODUCTION TO
BLOCKCHAIN
Ringaile Valiaugaite

2. ROADMAP
➤ History
➤ What is Blockchain?
➤ Use cases
➤ Blockchain Framework

3. HISTORY
➤ In 2008 Satoshi Nakamoto published white paper describing
the bitcoin digital currency.
➤ In 2009 he released the software that launched the first
blockchain Bitcoin.
➤ In 2013 Vitalik Buterin proposed Ethereum blockchain which
introduced smart contracts
➤ In 2015 Ethereum blockchain was released and is still one of
the most relevant blockchains nowadays.
Bitcoin white paper: https://bitcoin.org/bitcoin.pdf

4. ROADMAP
➤ History
➤ What is Blockchain?
➤ Use cases
➤ Blockchain Framework

5. DEFINITION
It is "an open, distributed ledger that can record transactions
between two parties efficiently and in a verifiable and
permanent way”.

6. ROADMAP
➤ History
➤ What is Blockchain?
➤ Use cases
➤ Blockchain Framework

7. USE CASES
➤ Voting system
➤ example: https://www.businessinsider.de/sierra-leone-blockchain-elections-2018-3?r=US&IR=T
➤ Supply Chain
➤ example: https://github.com/ringaile/eggxchain
➤ Kickstarter Funding Project
➤ example: https://github.com/ringaile/kickstart
➤ Collectable Games:
➤ example: https://www.cryptokitties.co

8. ROADMAP
➤ History
➤ What is Blockchain?
➤ Use cases
➤ Blockchain Framework
➤ Benefits

9. BLOCKCHAIN FRAMEWORK
➤ Transaction
➤ Wallet
➤ Signature
➤ Mempool
➤ Consensus
➤ Hashing
➤ Block
➤ Blockchain

10. TRANSACTION
➤ The unit that is recorded on blockchain.
➤ The transaction consists of:
➤ The transaction input which is sender’s address,
➤ The transaction output which is receiver’s address,
➤ The amount of cryptocurrency.

11. WALLET
➤ Contains private key, public key, wallet address
➤ Private key allows you to spend your money
➤ Public key is shareable key to receive money
➤ Wallet address - unique identifier of wallet

12. SIGNATURE
➤ Establishes proof of ownership for each transaction on the
blockchain
➤ Bitcoin requires digital signature made of private key and a
message
➤ It can be verified with public key, signature and a message

13. MEMPOOL
➤ Waiting place for all unconfirmed transactions before they are
added to blockchain.
➤ Transactions can leave the Mempool because they are added
to a blockchain, because of timeout or because of Mempool
size limit.

14. CONSENSUS
➤ Byzantine General’s Problem

15. CONSENSUS
➤ How the network reaches the agreement about which
transactions are most trustworthy.
➤ Bitcoin uses Proof of Work:
➤ Hard to produce, easy to verify,
➤ Each node(miner) tries to solve a problem,
➤ The first to solve builds a new block,
➤ Gets rewarded from transaction fees + network

16. HASHING
➤ A digital fingerprint of information
➤ A unique string of letters and
numbers that represent a set of
data
➤ Bitcoin uses SHA256 hashing
algorithm

17. BLOCK
➤ A container that holds the list of transactions to be added to
blockchain.
➤ A block header consists of time, Merkle root, nonce and
previous block’s hash.
Block live demo: https://anders.com/blockchain/block.html

18. BLOCKCHAIN
➤ A shared ledger that records the list of transactions.
➤ Blockchain demo: https://anders.com/blockchain/blockchain.html

19. Thank You!