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概覽

Golang is very popular among backend developers for building infrastructures and microservices. Go is a procedural programming language. Developed in 2007 by Robert Griesemer, Rob Pike, and Ken Thompson at Google, then launched in 2009 as an open-source programming language, Go is efficient for managing dependencies. Programs in Go are assembled by using packages.

Go has gained a lot of market share in past years and is currently used by major corporations. In this guide, we will cover creating an Ethereum address in Go using the Go-Ethereum Client library.

Learn how to connect to Ethereum network using Go here.

For our purposes today, we’ll use crypto and common packages of go-ethereum.

先決條件

• Go version 1.13 or above installed.
• 文字編輯器
• CLI

什麼是以太坊地址？

Authentication on any internet platform requires a username and password. You can think of an Ethereum address as your username, with the corresponding private key as your password (that you do not need to memorize). An Ethereum address is your unique identity on the blockchain, and it looks like this “0x6E0d01A76C3Cf4288372a29124A26D4353EE51BE”. The actual address is public and can be shared, but your private key must obviously be kept secret.  Your own Ethereum address is required for at least the following operations on the ETH network.

• Receiving/Sending ETH currency
• 簽署／發送交易
• Connecting to Applications

The following outlines the process of generating an Ethereum address using a private key.

• 首先會產生一個由 64 個字元（十六進位）組成的隨機私密金鑰（256 位元／32 位元組）。
  例如： 

0xf4a2b939592564feb35ab10a8e04f6f2fe0943579fb3c9c33505298978b74893

•  接著，會利用橢圓曲線數位簽章演算法（ECDSA），從生成的私鑰推導出一個 128（十六進位）字元（64 位元組）的公鑰。
  例如： 

0x04345f1a86ebf24a6dbeff80f6a2a574d46efaa3ad3988de94aa68b695f09db9ddca37439f99548da0a1fe4acf4721a945a599a5d789c18a06b20349e803fdbbe3

• 接著，將 (128 個字元 / 64 位元組) 的公鑰套用Keccak-256雜湊函數，以獲得一個 64 個字元 (32 位元組) 的雜湊字串。此字串的最後 40 個字元 / 20 位元組，加上前綴 0x，即成為最終的以太坊地址。
  例如：

0xd5e099c71b797516c10ed0f0d895f429c2781142

What is go-ethereum?

go-ethereum is the official GOlang implementation of Ethereum used to develop Ethereum nodes. go-ethereum has many packages for interactions and transactions with the Ethereum blockchain in Go.

Let’s see how we can easily generate a new Ethereum address in Go.

Generating an Ethereum address in Go

The first step here will be to check if Go is installed on our system. To do so, copy-paste the following in your terminal/cmd:

$ go version

If Go is not installed, follow the official installation guide for your specific OS.

Make sure you have the GCC compiler installed as well. 

For Ubuntu - use apt-get install build-essentials

For Windows - use https://jmeubank.github.io/tdm-gcc/download/

For Mac - using homebrew

$ brew install gcc

another faster option is getting XCode Command Line Tools using 

$ xcode-select --install

If you’re not familiar with Go, we recommend running their interactive tutorial to cover the basic syntax, methods, and concurrency handling. There are some exercises you can run without leaving your environment. Simply type the command below into your command line/terminal to run the tutorial locally:

$ go get golang.org/x/tour

Now type:

$ tour

Start by creating a file named address.go and copy-paste the following code into it. This code will create a private key, a public key using the private key, and an Ethereum address.

package main

import (
    "crypto/ecdsa"
    "fmt"
    "log"

    "github.com/ethereum/go-ethereum/common/hexutil"
    "github.com/ethereum/go-ethereum/crypto"
)

func main() {
    privateKey, err := crypto.GenerateKey()
    if err != nil {
        log.Fatal(err)
    }

    privateKeyBytes := crypto.FromECDSA(privateKey)
    fmt.Println("SAVE BUT DO NOT SHARE THIS (Private Key):", hexutil.Encode(privateKeyBytes))

    publicKey := privateKey.Public()
    publicKeyECDSA, ok := publicKey.(*ecdsa.PublicKey)
    if !ok {
        log.Fatal("cannot assert type: publicKey is not of type *ecdsa.PublicKey")
    }

    publicKeyBytes := crypto.FromECDSAPub(publicKeyECDSA)
    fmt.Println("Public Key:", hexutil.Encode(publicKeyBytes)) 

    address := crypto.PubkeyToAddress(*publicKeyECDSA).Hex()
    fmt.Println("Address:", address)
}

上述程式碼的說明

Line 1-10: Declaring the main package and adding necessary dependencies required to generate keys and address.

Line 12: Invoking the main function.

Line 13: Generating a random private key using the GenerateKey method from the crypto package.

Line 14-16: Checking for errors.

Line 18: Converting the private key to bytes using the FromECDSA method of the crypto/ecdsa package.

Line 19: Converting the private key to a hexadecimal string using the Encode method of hexutil package and printing the new string with a warning message.

Line 21: Generating a Public key from the Private key using the Public method of crypto package.

Line 22-28: Checking the type of Public key and then converting it to a hexadecimal string using the same process we saw for the Private key and printing the Public Key with a message.

Line 30: Generating an Ethereum address using PubkeyToAddress method of the crypto package, which accepts ECDSA public key, and returns an Ethereum address and storing it in a variable address.

Line 31: Printing the address along with a message “Address:”

Next, let’s create a module to track dependencies. If you’re not familiar with go, this is an essential step in setting up your project’s dependencies. With Go it’s relatively easy.

Simply type:

$ go mod init address

This will ensure the crypto and common packages included in your code are downloaded from GitHub and installed locally. It happens automatically, and the latest version should be pulled into your environment along with built-in Go modules. 

Now, let’s run our module.

$ go run address.go 

If you followed the instructions correctly and everything goes right, it must output something like this. The first line displays the private key, the Public key is second, and the third line displays your Ethereum address.

結論

Congratulations on creating a new Ethereum address with Go. This address can be used to interact with the Ethereum blockchain network and perform various operations. Look out for more easy-to-follow guides from QuikNode - your provider of affordable and lightning-fast Ethereum nodes. Learn how to get started with QuikNode and spin up your own Ethereum node in minutes and build the next big dApp!

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