Keystores

A keystore is a file containing an encrypted wallet private key. Keystores in go-ethereum can only contain one wallet key pair per file. To generate keystores first you must invoke NewKeyStore giving it the directory path to save the keystores. After that, you may generate a new wallet by calling the method NewAccount passing it a password for encryption. Every time you call NewAccount it will generate a new keystore file on disk.

Here's a full example of generating a new keystore account.

ks := keystore.NewKeyStore("./wallets", keystore.StandardScryptN, keystore.StandardScryptP)
password := "secret"
account, err := ks.NewAccount(password)
if err != nil {
  log.Fatal(err)
}

fmt.Println(account.Address.Hex()) // 0x20F8D42FB0F667F2E53930fed426f225752453b3

Now to import your keystore you basically need to invoke NewKeyStore again as usual and then call the Import method which accepts the keystore JSON data as bytes. The second argument is the password used to encrypt it in order to decrypt it. The third argument is to specify a new encryption password but we'll use the same one in the example. Importing the account will give you access to the account as expected but it'll generate a new keystore file! There's no point in having two of the same thing so we'll delete the old one.

Here's an example of importing a keystore and accessing the account.

file := "./wallets/UTC--2018-07-04T09-58-30.122808598Z--20f8d42fb0f667f2e53930fed426f225752453b3"
ks := keystore.NewKeyStore("./tmp", keystore.StandardScryptN, keystore.StandardScryptP)
jsonBytes, err := ioutil.ReadFile(file)
if err != nil {
  log.Fatal(err)
}

password := "secret"
account, err := ks.Import(jsonBytes, password, password)
if err != nil {
  log.Fatal(err)
}

fmt.Println(account.Address.Hex()) // 0x20F8D42FB0F667F2E53930fed426f225752453b3

if err := os.Remove(file); err != nil {
  log.Fatal(err)
}

Full code

keystore.go

package main

import (
    "fmt"
    "io/ioutil"
    "log"
    "os"

    "github.com/ethereum/go-ethereum/accounts/keystore"
)

func createKs() {
    ks := keystore.NewKeyStore("./tmp", keystore.StandardScryptN, keystore.StandardScryptP)
    password := "secret"
    account, err := ks.NewAccount(password)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(account.Address.Hex()) // 0x20F8D42FB0F667F2E53930fed426f225752453b3
}

func importKs() {
    file := "./tmp/UTC--2018-07-04T09-58-30.122808598Z--20f8d42fb0f667f2e53930fed426f225752453b3"
    ks := keystore.NewKeyStore("./tmp", keystore.StandardScryptN, keystore.StandardScryptP)
    jsonBytes, err := ioutil.ReadFile(file)
    if err != nil {
        log.Fatal(err)
    }

    password := "secret"
    account, err := ks.Import(jsonBytes, password, password)
    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(account.Address.Hex()) // 0x20F8D42FB0F667F2E53930fed426f225752453b3

    if err := os.Remove(file); err != nil {
        log.Fatal(err)
    }
}

func main() {
    createKs()
    //importKs()
}