Implementing the method suggest that will provide us with a fresh new brainkey

src/main/java/com/luminiasoft/bitshares/BrainKey.java

@@ -1,27 +1,64 @@
 package com.luminiasoft.bitshares;
 
-import org.bitcoinj.core.Base58;
-import org.bitcoinj.core.DumpedPrivateKey;
+import com.luminiasoft.bitshares.crypto.AndroidRandomSource;
+import com.luminiasoft.bitshares.crypto.SecureRandomStrengthener;
 import org.bitcoinj.core.ECKey;
-import org.bitcoinj.core.NetworkParameters;
 
 import java.io.UnsupportedEncodingException;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.Base64;
 
 /**
- * Created by nelson on 11/19/16.
+ * Class used to encapsulate all BrainKey-related operations.
  */
 public class BrainKey {
+    // The size of the word dictionary
+    public static final int DICT_WORD_COUNT = 49744;
+
+    // The required number of words
+    public static final int BRAINKEY_WORD_COUNT = 12;
 
     private ECKey mPrivateKey;
 
+    /**
+     * Method that will generate a random brain key
+     * @param words The list of words from the graphene specification dictionary.
+     * @return A random sequence of words
+     */
+    public static String suggest(String words){
+        String[] wordArray = words.split(",");
+        ArrayList<String> suggestedBrainKey = new ArrayList<String>();
+        assert(wordArray.length == DICT_WORD_COUNT);
+        SecureRandomStrengthener randomStrengthener = SecureRandomStrengthener.getInstance();
+        randomStrengthener.addEntropySource(new AndroidRandomSource());
+        SecureRandom secureRandom = randomStrengthener.generateAndSeedRandomNumberGenerator();
+        int index;
+        for(int i = 0; i < BRAINKEY_WORD_COUNT; i++){
+            index = secureRandom.nextInt(DICT_WORD_COUNT - 1);
+            suggestedBrainKey.add(wordArray[index].toUpperCase());
+        }
+        String result = String.join(" ", suggestedBrainKey.toArray(new String[suggestedBrainKey.size()]));
+        System.out.println("result: '"+result+"'");
+        return result;
+    }
+
+    /**
+     * BrainKey constructor that takes as argument a specific brain key word sequence and generates the
+     * private key and address from that.
+     * @param words The brain key specifying the private key
+     * @param sequence Sequence number
+     */
     public BrainKey(String words, int sequence) {
         String encoded = String.format("%s %d", words, sequence);
         try {
-            MessageDigest sha512 = MessageDigest.getInstance("SHA-512");
+            MessageDigest md = MessageDigest.getInstance("SHA-512");
+            byte[] bytes = md.digest(encoded.getBytes("UTF-8"));
             MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
-            mPrivateKey = ECKey.fromPrivate(sha256.digest(sha512.digest(encoded.getBytes("UTF-8"))));
+            byte[] result = sha256.digest(bytes);
+            mPrivateKey = ECKey.fromPrivate(result);
         } catch (NoSuchAlgorithmException e) {
             System.out.println("NoSuchAlgotithmException. Msg: " + e.getMessage());
         } catch (UnsupportedEncodingException e) {
@@ -29,7 +66,11 @@ public class BrainKey {
         }
     }
 
+    public String getPublicKey() {
+        return Base64.getEncoder().encodeToString(mPrivateKey.getPubKey());
+    }
+
     public ECKey getPrivateKey(){
-        return this.mPrivateKey;
+        return mPrivateKey;
     }
 }

src/main/java/com/luminiasoft/bitshares/Test.java

@@ -16,9 +16,10 @@ import org.spongycastle.crypto.Digest;
 import org.spongycastle.crypto.digests.SHA512Digest;
 import org.spongycastle.crypto.prng.DigestRandomGenerator;
 
-import java.io.IOException;
-import java.io.Serializable;
+import java.io.*;
 import java.lang.reflect.Type;
+import java.net.URL;
+import java.nio.file.Paths;
 import java.text.SimpleDateFormat;
 import java.util.*;
 
@@ -503,6 +504,14 @@ public class Test {
      * into the WIF at Main.WIF
      */
     public void testBrainKeyOperations(){
+        try {
+            String current = new java.io.File( "." ).getCanonicalPath();
+            File file = new File(current + "/src/main/java/com/luminiasoft/bitshares/brainkeydict.txt");
+
+            BufferedReader bufferedReader = new BufferedReader(new FileReader(file));
+            StringBuffer buffer = new StringBuffer();
+            String words = bufferedReader.readLine();
+            String suggestion = BrainKey.suggest(words);
             BrainKey brainKey = new BrainKey(Main.BRAIN_KEY, 0);
             ECKey key = brainKey.getPrivateKey();
             String wif = key.getPrivateKeyAsWiF(NetworkParameters.fromID(NetworkParameters.ID_MAINNET));
@@ -520,6 +529,12 @@ public class Test {
 
             byte[] pubKey3 = key.getPubKeyPoint().getEncoded(true);
             System.out.println("pub key compressed  : "+Base58.encode(pubKey3));
+
+        } catch (FileNotFoundException e) {
+            System.out.println("FileNotFoundException. Msg: "+e.getMessage());
+        } catch (IOException e) {
+            System.out.println("IOException. Msg: "+e.getMessage());
+        }
     }
 
 }

src/main/java/com/luminiasoft/bitshares/crypto/AndroidRandomSource.java

@@ -38,9 +38,10 @@ import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
+import java.nio.ByteBuffer;
 
 
-public class AndroidRandomSource implements RandomSource {
+public class AndroidRandomSource implements RandomSource, EntropySource {
 
     @Override
     public synchronized void nextBytes(byte[] bytes) {
@@ -58,4 +59,13 @@ public class AndroidRandomSource implements RandomSource {
             throw new RuntimeException("Unable to generate random bytes on this Android device", e);
         }
     }
+
+    @Override
+    public ByteBuffer provideEntropy() {
+        byte[] buffer = new byte[ 256 / 8];
+        nextBytes(buffer);
+        ByteBuffer byteBuffer = ByteBuffer.allocate(buffer.length);
+        byteBuffer.put(buffer, 0, buffer.length);
+        return byteBuffer;
+    }
 }