<p>As bitaddress.org BrainWallet says in its display</p>

<pre><code>Private Key (Wallet Import Format): 
5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj 
</code></pre>

<p>Wallet Import Format is the usual base58 armoring applied to the privatekey value with 'version' 0x80.
<br>See <a href="https://en.bitcoin.it/wiki/Wallet_import_format" rel="nofollow noreferrer">https://en.bitcoin.it/wiki/Wallet_import_format</a> or in more detail <a href="https://en.bitcoin.it/wiki/Base58Check_encoding" rel="nofollow noreferrer">https://en.bitcoin.it/wiki/Base58Check_encoding</a> . 
This is basically a duplicate of <a href="https://bitcoin.stackexchange.com/questions/21259/is-there-a-way-to-generate-a-brain-wallet-from-the-command-line-or-console">Is there a way to generate a brain wallet from the command line or console?</a> although that uses bash+dc rather than Java.</p>

<p>Not tested, but it looks to me like <code>VersionChecksummedBytes(0x80,bytes).toBase58()</code> does this.</p>

CC BY-SA 3.0
2016-04-24T05:45:48.830Z
Where is VersionChecksummedBytes? Is the method part of the bitcoinj library?
John Down
CC BY-SA 3.0
2016-04-25T03:12:43.433Z
@JohnDown yes it's in bitcoinj. It's a class (in Java by convention class names start with uppercase letter and method names start with lowercase letter) and is the superclass of the `Address` class your code already uses -- that's how I found it.
dave_thompson_085
CC BY-SA 3.0
2016-04-25T16:58:24.150Z
Can you further explain? The method is protected and I can't access it from my main class. Right now I have: Address output = new VersionChecksummedBytes(0x80,privateKeyByte).toBase58();
John Down
CC BY-SA 3.0
2016-04-25T21:11:30.390Z
See Java docs: https://bitcoinj.github.io/javadoc/0.12.3/index.html?overview-summary.html
John Down
CC BY-SA 3.0
2016-04-26T09:32:40.737Z
In the code (where I looked) actually the ctor is protected (and I didn't notice) but the method is public. (1) It's opensource so you could change it. (2) It's Java so you could override with reflection. (3) But the cleanest way is just make a *very* simple subclass, and use that. And (4) when you do, the result from `toBase58` (or `toString` which just wraps it) is `String`.
dave_thompson_085
CC BY-SA 3.0
2016-04-24T05:27:29.480Z
2016-04-24T05:38:54.943Z
2017-04-13T12:47:33.743Z
dave_thompson_085
<p>I think <code>new VersionedChecksummedBytes(0x80, priv).toBase58()</code> is the right idea, but the constructors are protected and I cannot find a static factory function. However, using the <code>getPrivateKeyEncoded</code> method of <code>ECKey</code>, we can obtain a <code>DumpedPrivateKey</code> object which derives from <code>VersionedChecksummedBytes</code>. We can also use the <code>getPrivateKeyAsWiF</code> method of <code>ECKey</code> which is more direct. Or we can do things manually:</p>

<pre><code>import java.math.BigInteger;
import org.bitcoinj.core.VersionedChecksummedBytes;
import org.bitcoinj.core.ECKey;
import org.bitcoinj.core.NetworkParameters;
import org.bitcoinj.core.Sha256Hash;
import org.bitcoinj.core.Base58;
import org.bitcoinj.params.MainNetParams;



public class Test {
  public static void main(String args[]){

  NetworkParameters mainNet = MainNetParams.get();
  String hex = "dba1e3e22415c56af772dee422add21b7382ea35f2af77852a8069d02e47ecf4";
  BigInteger big = new BigInteger(hex, 16); 
  ECKey key = ECKey.fromPrivate(big, false);  // uncompressed
  byte[] priv = key.getPrivKeyBytes();

  String wif1 = key.getPrivateKeyEncoded(mainNet).toBase58();
  System.out.println(wif1); // 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj

  String wif2 = key.getPrivateKeyAsWiF(mainNet);
  System.out.println(wif2); // 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj

  byte[] bytes = new byte[1 + 32 + 4];
  bytes[0] = (byte) 0x80;
  System.arraycopy(priv, 0, bytes, 1, 32);
  byte[] checksum = Sha256Hash.hashTwice(bytes, 0, 33);
  System.arraycopy(checksum, 0, bytes, 33, 4);
  String wif3 = Base58.encode(bytes);
  System.out.println(wif3); // 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj

  }
}
</code></pre>

<p>Beware that if you intend to do the same manual calculation for a compressed key, you need to add an additional byte <code>0x01</code> after the 32 bytes secret and just before the checksum. If you want to do the same thing for a testing network, replace the front version byte <code>0x80</code> by <code>0xef</code>.</p>

CC BY-SA 3.0
2016-08-22T09:44:45.493Z
2016-08-22T09:44:45.493Z
Sven Williamson
<p>I am trying to generate a public and private key set from a input string in Java. (Yes I am aware this can be a dangerous practice) I am using bitcoinj for a outside library.</p>

<p>I currently have:</p>

<pre><code> //public key generation from private key
 static String getPublicKey(byte[] privKey) {

    Address address = new Address(MainNetParams.get(), 
        Utils.sha256hash160(ECKey.fromPrivate(privKey, false).getPubKey()));

    return address.toString();

  }

 ///hash string to generate private key from string
 static byte[] sha256(String base) {
      try{
          MessageDigest digest = MessageDigest.getInstance("SHA-256");
          byte[] hash = digest.digest(base.getBytes("UTF-8"));
        return hash;
      } catch(Exception ex){
      throw new RuntimeException(ex);
      }
    }

 //encode private key as string to display
 static String privToString(byte[] hash) {

      StringBuffer hexString = new StringBuffer();

      for (int i = 0; i &lt; hash.length; i++) {
          String hex = Integer.toHexString(0xff &amp; hash[i]);
          if(hex.length() == 1) hexString.append('0');
          hexString.append(hex);
      }

      return hexString.toString();

  }
</code></pre>

<p>When I run the following:
Seed String: icecreampaintjob</p>

<p>I get the following:</p>

<p>Public: 1KdoiXMYFn2qa8uGGiNqfrwFRDu3j2qQNA</p>

<p>Private: dba1e3e22415c56af772dee422add21b7382ea35f2af77852a8069d02e47ecf4</p>

<p>Using bitaddress.org to cross verify I get:</p>

<p>Private: 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj (DOESN'T MACTH) </p>

<p>Public: 1KdoiXMYFn2qa8uGGiNqfrwFRDu3j2qQNA (MATCHES)</p>

<p>What am I missing?</p>

<wallet><private-key><public-key><sha256><brain-wallet>
Private Brain Key Generation and Public Address Not Matching Java
John Down
# Private Brain Key Generation and Public Address Not Matching Java

(Asked by: username_0 on 2016-04-24)

I am trying to generate a public and private key set from a input string in Java. (Yes I am aware this can be a dangerous practice) I am using bitcoinj for a outside library.
I currently have:
 //public key generation from private key
 static String getPublicKey(byte[] privKey) {

    Address address = new Address(MainNetParams.get(), 
        Utils.sha256hash160(ECKey.fromPrivate(privKey, false).getPubKey()));

    return address.toString();

  }

 ///hash string to generate private key from string
 static byte[] sha256(String base) {
      try{
          MessageDigest digest = MessageDigest.getInstance("SHA-256");
          byte[] hash = digest.digest(base.getBytes("UTF-8"));
        return hash;
      } catch(Exception ex){
      throw new RuntimeException(ex);
      }
    }

 //encode private key as string to display
 static String privToString(byte[] hash) {

      StringBuffer hexString = new StringBuffer();

      for (int i = 0; i < hash.length; i++) {
          String hex = Integer.toHexString(0xff & hash[i]);
          if(hex.length() == 1) hexString.append('0');
          hexString.append(hex);
      }

      return hexString.toString();

  }

When I run the following:
Seed String: icecreampaintjob
I get the following:
Public: 1KdoiXMYFn2qa8uGGiNqfrwFRDu3j2qQNA
Private: dba1e3e22415c56af772dee422add21b7382ea35f2af77852a8069d02e47ecf4
Using bitaddress.org to cross verify I get:
Private: 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj (DOESN'T MACTH) 
Public: 1KdoiXMYFn2qa8uGGiNqfrwFRDu3j2qQNA (MATCHES)
What am I missing?

**Tags:** wallet, private-key, public-key, sha256, brain-wallet


---

## 2 answers

### Answer by username_1 on 2016-04-24. Score: 1

As bitaddress.org BrainWallet says in its display
Private Key (Wallet Import Format): 
5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj 

Wallet Import Format is the usual base58 armoring applied to the privatekey value with 'version' 0x80.
See https://en.bitcoin.it/wiki/Wallet_import_format or in more detail https://en.bitcoin.it/wiki/Base58Check_encoding . 
This is basically a duplicate of Is there a way to generate a brain wallet from the command line or console? although that uses bash+dc rather than Java.
Not tested, but it looks to me like VersionChecksummedBytes(0x80,bytes).toBase58() does this.

> **Comments:**
> **username_0**: Where is VersionChecksummedBytes? Is the method part of the bitcoinj library?  
> **username_1**: @JohnDown yes it's in bitcoinj. It's a class (in Java by convention class names start with uppercase letter and method names start with lowercase letter) and is the superclass of the `Address` class your code already uses -- that's how I found it.  
> **username_0**: Can you further explain? The method is protected and I can't access it from my main class. Right now I have: Address output = new VersionChecksummedBytes(0x80,privateKeyByte).toBase58();  
> **username_0**: See Java docs: https://bitcoinj.github.io/javadoc/0.12.3/index.html?overview-summary.html  
> **username_1**: In the code (where I looked) actually the ctor is protected (and I didn't notice) but the method is public. (1) It's opensource so you could change it. (2) It's Java so you could override with reflection. (3) But the cleanest way is just make a *very* simple subclass, and use that. And (4) when you do, the result from `toBase58` (or `toString` which just wraps it) is `String`.  

---

### Answer by username_2 on 2016-08-22. Score: 0

I think new VersionedChecksummedBytes(0x80, priv).toBase58() is the right idea, but the constructors are protected and I cannot find a static factory function. However, using the getPrivateKeyEncoded method of ECKey, we can obtain a DumpedPrivateKey object which derives from VersionedChecksummedBytes. We can also use the getPrivateKeyAsWiF method of ECKey which is more direct. Or we can do things manually:
import java.math.BigInteger;
import org.bitcoinj.core.VersionedChecksummedBytes;
import org.bitcoinj.core.ECKey;
import org.bitcoinj.core.NetworkParameters;
import org.bitcoinj.core.Sha256Hash;
import org.bitcoinj.core.Base58;
import org.bitcoinj.params.MainNetParams;



public class Test {
  public static void main(String args[]){

  NetworkParameters mainNet = MainNetParams.get();
  String hex = "dba1e3e22415c56af772dee422add21b7382ea35f2af77852a8069d02e47ecf4";
  BigInteger big = new BigInteger(hex, 16); 
  ECKey key = ECKey.fromPrivate(big, false);  // uncompressed
  byte[] priv = key.getPrivKeyBytes();

  String wif1 = key.getPrivateKeyEncoded(mainNet).toBase58();
  System.out.println(wif1); // 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj

  String wif2 = key.getPrivateKeyAsWiF(mainNet);
  System.out.println(wif2); // 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj

  byte[] bytes = new byte[1 + 32 + 4];
  bytes[0] = (byte) 0x80;
  System.arraycopy(priv, 0, bytes, 1, 32);
  byte[] checksum = Sha256Hash.hashTwice(bytes, 0, 33);
  System.arraycopy(checksum, 0, bytes, 33, 4);
  String wif3 = Base58.encode(bytes);
  System.out.println(wif3); // 5KV1o7tRK8pNqrPNYyi38nrik9r2Y85sjdgFDttnDiT1uZrQ1fj

  }
}

Beware that if you intend to do the same manual calculation for a compressed key, you need to add an additional byte 0x01 after the 32 bytes secret and just before the checksum. If you want to do the same thing for a testing network, replace the front version byte 0x80 by 0xef.


---

