104 lines
3.7 KiB
Java
104 lines
3.7 KiB
Java
package de.bitsharesmunich.graphenej;
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import de.bitsharesmunich.graphenej.crypto.AndroidRandomSource;
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import de.bitsharesmunich.graphenej.crypto.SecureRandomStrengthener;
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import org.bitcoinj.core.DumpedPrivateKey;
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import org.bitcoinj.core.ECKey;
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import org.bitcoinj.core.NetworkParameters;
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import java.io.UnsupportedEncodingException;
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import java.security.MessageDigest;
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import java.security.NoSuchAlgorithmException;
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import java.security.SecureRandom;
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import java.util.ArrayList;
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/**
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* Class used to encapsulate all BrainKey-related operations.
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*/
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public class BrainKey {
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// The size of the word dictionary
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public static final int DICT_WORD_COUNT = 49744;
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// The required number of words
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public static final int BRAINKEY_WORD_COUNT = 12;
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private ECKey mPrivateKey;
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/**
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* Method that will generate a random brain key
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*
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* @param words The list of words from the graphene specification
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* dictionary.
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* @return A random sequence of words
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*/
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public static String suggest(String words) {
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String[] wordArray = words.split(",");
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ArrayList<String> suggestedBrainKey = new ArrayList<String>();
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assert (wordArray.length == DICT_WORD_COUNT);
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SecureRandomStrengthener randomStrengthener = SecureRandomStrengthener.getInstance();
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randomStrengthener.addEntropySource(new AndroidRandomSource());
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SecureRandom secureRandom = randomStrengthener.generateAndSeedRandomNumberGenerator();
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int index;
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for (int i = 0; i < BRAINKEY_WORD_COUNT; i++) {
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index = secureRandom.nextInt(DICT_WORD_COUNT - 1);
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suggestedBrainKey.add(wordArray[index].toUpperCase());
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}
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StringBuilder stringBuilder = new StringBuilder();
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for(String word : suggestedBrainKey){
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stringBuilder.append(word);
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stringBuilder.append(" ");
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}
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System.out.println("Suggestion: '"+stringBuilder.toString().trim()+"'");
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return stringBuilder.toString().trim();
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}
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/**
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* BrainKey constructor that takes as argument a specific brain key word
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* sequence and generates the private key and address from that.
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*
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* @param words The brain key specifying the private key
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* @param sequence Sequence number
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*/
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public BrainKey(String words, int sequence) {
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String encoded = String.format("%s %d", words, sequence);
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try {
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MessageDigest md = MessageDigest.getInstance("SHA-512");
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byte[] bytes = md.digest(encoded.getBytes("UTF-8"));
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MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
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byte[] result = sha256.digest(bytes);
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mPrivateKey = ECKey.fromPrivate(result);
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} catch (NoSuchAlgorithmException e) {
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System.out.println("NoSuchAlgotithmException. Msg: " + e.getMessage());
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} catch (UnsupportedEncodingException e) {
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System.out.println("UnsupportedEncodingException. Msg: " + e.getMessage());
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}
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}
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/**
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* Gets the array of bytes representing the public key.
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* @return
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*/
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public byte[] getPublicKey() {
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return mPrivateKey.getPubKey();
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}
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/**
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* Returns the private key as an instance of the ECKey class.
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* @return
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*/
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public ECKey getPrivateKey() {
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return mPrivateKey;
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}
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/**
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* Returns the private key in the Wallet Import Format for the uncompressed private key.
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* @see <a href="https://en.bitcoin.it/wiki/Wallet_import_format">WIF</a>
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* @return
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*/
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public String getWalletImportFormat(){
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DumpedPrivateKey wif = this.mPrivateKey.decompress().getPrivateKeyEncoded(NetworkParameters.fromID(NetworkParameters.ID_MAINNET));
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return wif.toString();
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}
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}
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