Ethereum for Ruby - Speaker Deck

Ethereum for Ruby

by Yuta Kurotaki

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Ethereum for Ruby Yuta Kurotaki

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Yuta Kurotaki @kurotaky RubyKaigi Speaker 2018 RailsGirls Coach 4,7~10,12,13th Yokohama.rb, K-Ruby Kagoshima RubyKaigi 01 Organizer Goods Sponsor (SUZURI, GMO Pepabo, Inc.) eth.rb Maintainer

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Contents • What is Ethereum? • Ethereum Keys and Addresses • Ethereum Signatures • Ethereum Transaction • Interact with Smart Contract

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What is Ethereum?

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Ethereum Blockchain • It is the Ethereum Blockchain invented by Vitalik in 2013 • Trustless on the blockchain • It's called a world computer

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Ethereum Blockchain https://ethereum.org/en/whitepaper/ APPLY(S,TX) -> S'

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Ethereum Blockchain https://ethereum.org/en/whitepaper/

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Etherscan https://etherscan.io/

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eth.rb • Let's take a look into the world of blockchain with eth.rb! • https://github.com/q9f/eth.rb

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Ethereum Keys and Addresses

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Blockchain Wallet • When users create a wallet such as MetaMask, an address of 0xabc.... is created. • This address is required on Ethereum https://metamask.io/

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Eth::Key • The library can create private/public key pairs • This can also show the required address on ethereum

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Address 0x4cbeFF8966586874362ce4313D8f80cD404838a3

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Address • Calculate hash value of public key with Keccak256 • Public key = K, last 20bytes of Keccak256(K) • Returns with 0x; 42 characters (40 without 0x)

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EIP-55 • If the checksum is 8 or higher, the corresponding address letter is uppercase to prevent input errors. • EIP(Ethereum Improvement Proposals)

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EIP(Ethereum Improvement Proposals) https://eips.ethereum.org/EIPS/eip-55 https://eips.ethereum.org/EIPS/eip-721

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EIP-55 • Addresses are not case sensitive • Can be veri fi ed if the checksum is used

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ENS • Ethereum Domain Name Service • kurotaky.eth https://ens.domains/ https://eips.ethereum.org/EIPS/eip-137

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Ethereum Signatures

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Ethereum Signatures • ECDSA (Eliptic Curve Digital Signature Algorithm) • This is used for three purposes 1. proof of authorization to make ETH payments or execute smart contracts 2. proof that the signature is non-repudiation 3. proof that no one has modi fi ed the transaction data since it was signed https://ethereum.org/en/developers/docs/transactions/

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personal_sign •

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sign

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sign

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Signature.verify

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EIP-155 https://eips.ethereum.org/EIPS/eip-155

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Chain ID

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Transaction

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Transaction https://ethereum.org/en/whitepaper/

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Go Ethereum(geth) • Of fi cial Go implementation of the Ethereum protocol • geth --dev --http --ipcpath /tmp/geth.ipc https://geth.ethereum.org/

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geth

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Send ETH to another address • Geth (use http server) • use Eth::Client.create

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transfer_and_wait • 0.000000000000000001 = 1Wei • 0.000000000000000001 * 99000000000000000000 = 99ETH

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Eth::Unit

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Interact with Smart Contract

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Smart Contract • Can automatically execute contracts • Can execute programs on the blockchain

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Use Cases • DeFi (Decentralized Finance) • Identity (sign in with an ethereum account) • Cryptoeconomics • Stickers/badges • etc.

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Solidity https://docs.soliditylang.org/en/v0.8.16/introduction-to-smart-contracts.html#simple-smart-contract

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Solidity Compiler dummy.sol Solidity Compiler (solc) byte code 6080604052..... EVM (Ethereum Virtual Machine) ABI (Application Binary Interface) EVM opcode PUSH1 0x80 PUSH1 0x40 MSTORE

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Eth::Contract.from_ fi le • Conversion from sol fi les to Ruby objects

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dummy.sol

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ABI & bin

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Deployment of Smart Contracts • Deployment of Smart Contracts • call() and transact_and_wait()

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Sample App 1 Sign-In with Ethereum https://github.com/q9f/ethereum-on-rails

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User • username • eth_address • eth_nonce

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Sample App 2 Non-Fungible Token App https://gihyo.jp/magazine/wdpress/archive/2022/vol130 https://github.com/kurotaky/sample-rails-dapp

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Let's try it! • This is a Rails application for creating Non Fungible Tokens • Please try it out !

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Conclusion

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Conclusion • Ethereum Blockchain Overview • How Ethereum Addresses Work and EIP • Overview of ethereum signatures • About executing smart contracts using eth.rb

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Future of eth.rb • Language diversity is important so that Ruby can also connect with the Ethereum world! • More examples of creating DApps with Ruby and Rails • Make it easy to connect to existing Rails applications

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Acknowledgements • @ethmarek • He brought me into the world of Ethereum.rb • @q9f • He promotes and maintains the eth.rb project with us • GMO Pepabo Web3 Development Team • RubyKaigi staff, organizers, committers and attendees

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Thank You! @kurotaky