We are interconnected. We build a blockchain, not only allow transaction data but also store programs. Decentralize any application. Instead of launching an application like facebook. What if we can run facebook in all computers at the same time. Build world super computer in distributed manner using blockchain.

All facilitated through blockchain. Immutable.

What is smart contract? –>program What is a contract? set of rules or clauses that people agree. Conditions. program speak the same language. if this then that…

code on the blockchain.

In bitcoin language - bitcoin script In Ethereum - solidity

difference turing completeness of a language bitcoin no/ solidity yes turing-completeness means you can code any logic into that language. It is a conceptual notion.

Why bitcoin not turing-complete? because it does not have a loop. Intentionally did not include loop. It can slow down the blockchain, if it is infinite loop or long loop.

Vitalic Butalin Everybody in a network will have a copy of the contract.

  1. Each node has history of all smart contracts
  2. History of all transactions
  3. Every node has a current state of all smart contracts

CHeck the checkbox whenever it is moved from one to another. Smart contract in not disputable. See details what happend to the product.

DAPP consist of frontend & backend(smart contract, blockchain)

Ethereum Virtual MAchin and Gas *Security What are most common security threat in smart contract: 1) loop 2) virus on contract and send to all computers then all infected. If they can access to private files.

solution 1: Gas. For any computation, developers or people should pay for calculation. Gas per every calculation(bitwise addition and so on). If gas runs out there will be no loop infinite. It makes people write good code, because people will write good code as possible –> efficient programs are generated. ex) website load immidiately. ex) ETH Gas Station - how much you will be paying and etc. If just use ETH since price fluctuates hard to predict how much it will be…..

solution 2: WHen you participate in Ethereum you get EVM. Virtual machine running on your computer. encapsulates everything that runs there. computer inside computer. Nothing can get out of VM. Does not know anything out of the machine. If it goes wrong it will go wrong only in VM, then delete and reinstall. Because it is secluded or detached, it won’t access to private files.

Ether goal is not use for transaction or invest, but ETH is to create system and network where people can write code and pay with ETH. Create application that can run on blockchain.

For turing completeness you have to pay. It is not only cryptocurrency. To facilitate the whole system.