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Blockchain, smart contracts - introduction


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Blockchain, smart contracts - introduction

  1. 1. Blockchain, smart contracts introduction © Lukasz Jarmulowicz 2016
  2. 2. TL; DR - History, background - Solved problems - How it works (wallets, transactions, mining) - Ethereum, Smart contracts - Profit
  3. 3. Why bitcoin?
  4. 4. Ledger A general ledger contains all the accounts for recording transactions relating to a company's assets, liabilities, owners' equity, revenue, and expenses. Purpose: To have financial statement
  5. 5. Double spendingByzantine Generals Problem More generally, the B.G.P. poses the question of how to establish trust between otherwise unrelated parties over an untrusted network like the Internet. The problem to be solved is: ● All loyal generals need to decide upon the same plan of action. ● A small number of traitors cannot cause the loyal generals to adopt a bad plan.
  6. 6. Bitcoin In October 2008, “Satoshi Nakamoto” published a paper describing the bitcoin digital currency. In January 2009, Nakamoto released the first bitcoin software that launched the network and the first units of the bitcoin cryptocurrency, called bitcoins.
  7. 7. Distributed ledger - Blockchain The block chain is a shared public ledger on which the entire Bitcoin network relies. All confirmed transactions are included in the block chain. This way, Bitcoin wallets can calculate their spendable balance and new transactions can be verified to be spending bitcoins that are actually owned by the spender.
  8. 8. A mysterious new technology emerges, seemingly out of nowhere, but actually the result of two decades of intense research and development by nearly anonymous researchers. ... Eventually mainstream products, companies and industries emerge to commercialize it; its effects become profound; and later, many people wonder why its powerful promise wasn’t more obvious from the start. ... What technology am I talking about? Personal computers in 1975, the Internet in 1993, and – I believe – Bitcoin in 2014 Marc Andreesen, creator of Netscape Navigator
  9. 9. Davos 2016 - big attention
  10. 10. Even in Russia...
  11. 11. Ok, ok.. but how it works ?
  12. 12. Wallet
  13. 13. Transactions
  14. 14. Transaction signing - scripts inside Small program inside each transaction that gets executed to decide if a transaction is valid
  15. 15. Transaction chain gives balance
  16. 16. Confirming transactions - mining
  17. 17. Mining - blocks Bitcoin mining is the process that puts transactions into a block, to make sure everyone has a consistent view of the transaction log. Mining is also the mechanism for new bitcoins to enter the system. When a block is successfully mined, new bitcoins are generated in the block and paid to the miner. This mining bounty is large - currently 25 bitcoins per block (~ $14,000).
  18. 18. This is blockchain
  19. 19. Recap Wallets Transactions Transaction chain > balance Mining > creating linked blocks Example?
  20. 20. Ethereum, smart contracts
  21. 21. Ethereum was initially proposed by Vitalik Buterin in late 2013 and in 2014 he described it as "A Next-Generation Cryptocurrency and Decentralized Application Platform". Ethereum's live blockchain was launched on 30 July 2015. The Ethereum software project was initially developed by a Swiss company, Ethereum Switzerland GmbH (EthSuisse) and a Swiss non-profit foundation, the Ethereum Foundation.
  22. 22. Ethereum Virtual Machine Programmable blockchain - Rather than give users a set of pre-defined operations (e.g. bitcoin transactions), Ethereum allows users to create their own operations of any complexity they wish. Bitcoin blockchain was purely a list of transactions, Ethereum’s basic unit is the account. The Ethereum blockchain tracks the state of every account, and all state transitions on the Ethereum blockchain are transfers of value and information between accounts. Platform for many different types of decentralized blockchain applications, including but not limited to cryptocurrencies.
  23. 23. Smart contracts ● Contracts lives on the Ethereum blockchain ● Have own Ethereum address and balance ● Can send and receive transactions ● “Activated” when you send a transaction to it
  24. 24. Smart contracts ● 4 Ethereum high level languages ○ Solidity (similar to js) ● Compile (Mix IDE) ● Deploy (you pay for execution gas - > eth) ● Interacting with smart contracts ● Mining - little different than bitcoin (few changes)
  25. 25. Plans for smart contracts usage
  26. 26. ETHEREUM AS A ‘WORLD COMPUTER’ Computation on Ethereum is slow and expensive. (currently similar to smartphone?!) For computation, there are better, cheaper and faster alternatives that don’t require blockchains and all that. Ethereum can create various forms of economic alignment, shared purpose and coordination between thousands of anonymous people, at a fraction of a cost compared to alternatives (legal frameworks). Sharing economy (ex. uber, airbnb) will be everywhere.
  27. 27. Decentralized autonomous organizations (“DAO”) ● Best comparable to a digital company, but without an attached legal entity ● The Owner (kind of admin) can add (or remove) voting members to the organization ● Any member can make a proposal (by sending transaction or execute contract) ● People vote on proposals ● Allows people to participate in risks & rewards of digital ventures
  28. 28. Cons Scalability Confidentiality Valuations No Buyer Protection - real time
  29. 29. Thank you. Questions? © Lukasz Jarmulowicz 2016

Notas del editor

  • Fra Luca Bartolomeo de Pacioli - XV wiek - wspolpracownik LEO
    matematyk, uważany za "ojca rachunkowości“

    Sprawozdanie finansowe – uporządkowane przedstawienie sytuacji finansowej i finansowych wyników działalności podmiotu gospodarczego
    Ask Aleksander if it’s important
  • The problem was originally framed in terms of a group of generals camped around an enemy city.

    - Plan (atak, ucieczka, kiedy atak)
    but can't ever meet in person.

    The only means of communication is by messenger sent by foot from one camp to another. Further complicating matters, not every general can be trusted to be loyal to the cause.

    Jest uogólnieniem problemu dwóch armii[3] albo problemu dwóch generałów.
  • A Bitcoin transaction moves bitcoins between one or more inputs and outputs. Each input is a transaction and address supplying bitcoins. Each output is an address receiving bitcoin, along with the amount of bitcoins going to that address.
  • IBM Blockchain?