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Resource slides for blockchain related question
- 1. Resource Slides for Q&A
- 2. Ethereum hard fork • Why will DAO attack cause hard fork for Ethereum? • the inherent vulnerabilities in The DAO’s smart contract leaves the door open to future attacks. Each child DAO created is an effective copy of the original, bringing with it all of the flaws contained within. It’s because of this that some are pushing for a rule change in the ethereum network. • Effect of hard fork? it would allow developers to freeze funds taken from The DAO, and thus secure funds until they can be recovered. the move threatens the integrity of the ethereum blockchain and the project as a whole.
- 3. Ethereum hard fork • How can the change happen? • Release new version for numerous client(Go,C++,Rust,Python,Java,Ruby,Haskell,JS, enforce upgrade of client • Enforced by new rule: DAO challenge response after an eth handshake • What exactly is the change? • 35 files changed, including modifications to the configuration/genesis, p2p networking, and EVM protocol. • E.g. necessary consensus modifications to header validation rules
- 4. Public vs private blockchain Public Private Access Open read/write access to database Permissioned read and/or write access to database Speed Slower Faster Security Based on consensus algorithm Pre-approved participants Identity Anonymous/pseudonymous Known identities Asset Native assets Any asset Privacy Data publicly available to whoever connect to the blockchain Privacy policy for data same as in traditional database Transaction fee Transaction fee required Completely free/inexpensive transactions Immutability Secured by hashing power Secured by distributed consensus Examples Bitcoin, Ethereum, Hyperledger Ripple, Blockstream, Multichain
- 5. Smart contract Pre-written logic(computer code) Stored and replicated on a distributed storage platform(blockchain) Execute/run by a network of computers(e.g. blockchain miners) Result in ledger updates(e.g. cryptocurrency payment) ______________________________________________________________ = General purpose computation takes place on blockchain If blockchains give us distributed trustworthy storage, then smart contracts give us distributed trustworthy calculations.
- 6. Smart contract examples • Decentralized Twitter • a decentralised microblogging service • provides basic Twitter-like functionality to tweet messages of up to 160 characters. • Decentralized Virtual World & Crypto-Real Estate • Ξtheria is a virtual world • players can own tiles, farm them for blocks, and build things. • Managing identity • plans to bring "ease and simplicity" to the process of identification for businesses wishing to onboard new customers
- 7. Smart contract examples • Slock.it: IoT + Blockchain • blockchain smart contract to do access control(control physical lock) • Enable Rent, sell or share anything - without middlemen https://www.youtube.com/watch?v=-Ht23KXic1k
- 8. Smart contract Good vs Bad What’s good? • Express business logic as computer program • Represent logic triggering event as a message to the program • Use digital signatures to prove who send the messages • Everything is transparent to everyone in the blockchain What’s bad? • Execution of every program for every message on every blockchain node (global execution) • Works poorly for high transaction throughput • Transaction order is critical, unconfirmed transaction has no predictable outcome
- 9. Cryptocurrencies = Cryptographic based digital money • Definition • Digital money • Using cryptography functions to secure transactions • No centralized trusted party to operate the currency • Characteristic • With digital signature to indicate ownership • Digital transaction made with owner’s signature • Everybody can verify ownership of crytocurrency, everyone can see transaction record of crytocurrency • Not possible to double spend • Who owns it? • Anyone could own cryptocurrency, with a digital wallet • Who runs it? • The blockchain miners (A group of computers) • Examples: • Bitcoin, Ether, Ripple, Colored coins 9
- 10. How to get cryptocurrency? • Purchase over an exchange • For Investors • Purchase with real world currency • Be a miner and do mining • People with internet and hardware • Steps: • Choose a cryptocurrency to mine(bitcoin, Ether, other altcoin: Litecoin, Dogecoin etc) • Setup wallet to keep your wealth • Download and install corresponding mining software • Configuration – join some mining pool • Run mining program, get cryptocurrency from rewards
- 11. How to get cryptocurrency? • Transfer • Someone transfer you their crytocurrency • Steps: • Download an wallet application • Create account with the cryptocurrency • Expose your wallet address to the sender • Sender transfer cryptocurrency and you receive it.
- 12. Number of guesses(hashes) before you get a Block hash value? 1.The number of guesses increasing in time. 2.Current value: 1.6*1018 hash/s * 10 min/block = 1.6*1018 hash/s * 600 sec/block = 9.6 * 1020 hash/block
- 13. Why Blockchain is begin with fintech? Other than the payment what does it do in the finance? • Part 1: Blockchain is created to solve The Byzantine General’s Problem. Blockchain didn’t decided to start with Fintech, instead, Blockchain is born because of Fintech(people extract Blockchain idea from bitcoin). • Part 2: The things blockchain can do in the finance area • Virtual wallet / payments / exchange offering (Bitreserve, BitPesa) • Process payments (BitPay, Coinbase) • Clearing and settlement solutions (Hyperledger, Serica) • Developing and offering cryptocurrency denominated products (SolidX, Tinker)
Editor's Notes
- #3: Source: http://www.coindesk.com/dao-counter-attack-ethereum/
- #4: Source: enforce upgrade: https://www.reddit.com/r/ethereum/comments/4tjzi4/time_to_upgrade_your_client_whether_you_are_pro/ DAO challenge: https://github.com/ethereum/go-ethereum/pull/2795 What exactly changed: https://github.com/ethereum/go-ethereum/pull/2814
- #5: Ref Source: http://www.coindesk.com/state-of-blockchain-q1-2016/ https://magnr.com/blog/technology/private-vs-public-blockchains-bitcoin/ http://www.slideshare.net/coinspark/understanding-private-blockchains
- #6: There are many debates over what smart contract is. One person has summarized that no-one has a clue…. Meaning the smart contract is at emerging stage where people don’t know what its future is going to be like. Though there is no concrete definition of what smart contract is, there are some characteristics people use to describe it. For instance, it is nothing fancy but pre-written business logic and it is stored and replicated on a distributed ledger. When it is running or executed it is executed by a network of computers instead of a single centralized server. Source: https://bitsonblocks.net/2016/02/01/a-gentle-introduction-to-smart-contracts/
- #7: http://www.coindesk.com/7-cool-decentralized-apps-built-ethereum/ 1. Decentrailized twitter https://github.com/yep/eth-tweet http://etheria.world/whatis.html http://kyc-chain.com/
- #9: Ref: smart contracts- the good, the bad and the lazy Questions: Useful example of smart contract. 2-3 slide of introduction to it. Good point Bad thing about it(Refer to Multichain)
- #10: https://www.youtube.com/watch?v=fOMVZXLjKYo http://com-http.us/
- #11: http://www.bestbitcoinexchange.io/
- #14: Part 2 reference: https://www2.deloitte.com/content/dam/Deloitte/ie/Documents/FinancialServices/IE_Cons_Blockchain_1015.pdf