path: root/cmd/ethkey/changepassphrase.go

package main

import (
    "fmt"
    "io/ioutil"
    "strings"

    "github.com/ethereum/go-ethereum/accounts/keystore"
    "github.com/ethereum/go-ethereum/cmd/utils"
    "gopkg.in/urfave/cli.v1"
)

var newPassphraseFlag = cli.StringFlag{
    Name:  "newpasswordfile",
    Usage: "the file that contains the new passphrase for the keyfile",
}

var commandChangePassphrase = cli.Command{
    Name:      "changepassphrase",
    Usage:     "change the passphrase on a keyfile",
    ArgsUsage: "<keyfile>",
    Description: `
Change the passphrase of a keyfile.`,
    Flags: []cli.Flag{
        passphraseFlag,
        newPassphraseFlag,
    },
    Action: func(ctx *cli.Context) error {
        keyfilepath := ctx.Args().First()

        // Read key from file.
        keyjson, err := ioutil.ReadFile(keyfilepath)
        if err != nil {
            utils.Fatalf("Failed to read the keyfile at '%s': %v", keyfilepath, err)
        }

        // Decrypt key with passphrase.
        passphrase := getPassphrase(ctx)
        key, err := keystore.DecryptKey(keyjson, passphrase)
        if err != nil {
            utils.Fatalf("Error decrypting key: %v", err)
        }

        // Get a new passphrase.
        fmt.Println("Please provide a new passphrase")
        var newPhrase string
        if passFile := ctx.String(newPassphraseFlag.Name); passFile != "" {
            content, err := ioutil.ReadFile(passFile)
            if err != nil {
                utils.Fatalf("Failed to read new passphrase file '%s': %v", passFile, err)
            }
            newPhrase = strings.TrimRight(string(content), "\r\n")
        } else {
            newPhrase = promptPassphrase(true)
        }

        // Encrypt the key with the new passphrase.
        newJson, err := keystore.EncryptKey(key, newPhrase, keystore.StandardScryptN, keystore.StandardScryptP)
        if err != nil {
            utils.Fatalf("Error encrypting with new passphrase: %v", err)
        }

        // Then write the new keyfile in place of the old one.
        if err := ioutil.WriteFile(keyfilepath, newJson, 600); err != nil {
            utils.Fatalf("Error writing new keyfile to disk: %v", err)
        }

        // Don't print anything.  Just return successfully,
        // producing a positive exit code.
        return nil
    },
}