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I use web3j to create my ethereum wallet.the Code just like down

import org.web3j.crypto.Bip39Wallet;
import org.web3j.crypto.Credentials;
import org.web3j.crypto.ECKeyPair;
import org.web3j.crypto.WalletUtils;

wallet = WalletUtils.generateBip39Wallet(password, new File(keystorePath));
// keystore's file name
String keystoreFileName = wallet.getFilename();
// my mnemonic
String mnemonic = wallet.getMnemonic();

I can use this code get my address

Credentials credentials = WalletUtils.loadBip39Credentials(password, mnemonic);
String address = credentials.getAddress();

I can import my wallet by this:

Credentials credentials = WalletUtils.loadBip39Credentials(password, mnemonic);

but in this way I need password & mnemonic,How I import or recovery my wallet by mnemonic without password,because some wallet app just like metamask or imtoken , they don't need the old password that I create my wallet and the can reset a new password.

In other words,recovery or import the wallet just need mnemonic,how I do it by web3j

enter image description here

Is ereryone can tell me how to do it by web3j.thank u very much.

  • 1
    I think the password is new password as shown in your metamask screen shot – Ha ĐANG Aug 23 '18 at 3:54
  • yes.Just need mnemonic and u can set a new password.It's meaning that I can reset my wallet just by mnemonic – chenhao597 Aug 23 '18 at 4:02
  • Ah, I mean the password in WalletUtils.loadBip39Credentials(password, mnemonic); also new password, not the current password then you user can input any new password to recover the wallet – Ha ĐANG Aug 23 '18 at 4:14
  • @HaĐANG right.I want to get it you user can input any new password to recover the wallet but now my user recover the wallet need password – chenhao597 Aug 23 '18 at 8:49
0

I think that only is password of Metamask, it is not used for wallet encryption. You can recovery wallet with bip39 package:

https://iancoleman.io/bip39/

https://www.npmjs.com/package/bip39

let seed = await bip39.mnemonicToSeed(mnemonicPhrase, password); //password can null
let HDwallet = await etherHDkey.fromMasterSeed(seed);
let wallet = HDwallet.derivePath(hdPath + "/" + index).getWallet();
0

For Bip44 wallets Web3j will use the derivation path m/44/60'/0'/0. The more commonly used path is m/44/60'/0'/0/0 (with an extra /0).

The following code will derive the correct address given a valid mnemonic.

String mnemonic = "abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about";
String password = "";
byte[] seed = MnemonicUtils.generateSeed(mnemonic, password);
Bip32ECKeyPair masterKeypair = Bip32ECKeyPair.generateKeyPair(seed);
final int[] path = {44 | HARDENED_BIT, 60 | HARDENED_BIT, 0 | HARDENED_BIT, 0, 0};
Bip32ECKeyPair childKeypair = Bip32ECKeyPair.deriveKeyPair(masterKeypair, path);
Credentials credential = Credentials.create(childKeypair);

System.out.println(credential.getAddress());

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