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110
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1 package christie.blockchain;
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2
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3 import org.bouncycastle.util.Arrays;
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4 import org.bouncycastle.util.BigIntegers;
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5
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6 import java.io.ByteArrayOutputStream;
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7 import java.math.BigInteger;
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8 import java.nio.charset.Charset;
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9
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10
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11 public class Miner {
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12
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13 HashUtil hashUtil = new HashUtil();
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14
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15
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16 public void mineBlock(Block newBlock, int difficulty) {
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17 long nonce = 0;
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18
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19
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20 //byte[] target = new String(new char[difficulty]).replace('\0', '0').getBytes();
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21 String target = new String(new char[difficulty]).replace('\0', '0');
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22 byte[] hash = newBlock.getPresentHashWithoutNonce();
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23
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24 String hashStr = new String(hashUtil.sha256(hash), Charset.forName("utf-8"));
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25
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26
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27 while(!hashStr.substring( 0, difficulty).equals(target)) {
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28 nonce ++;
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29 byte[] concat = Arrays.concatenate(hash, BigInteger.valueOf(nonce).toByteArray());
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30 hashStr = new String(hashUtil.sha256(concat), Charset.forName("utf-8"));
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31 }
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32 newBlock.setNonce(nonce);
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33 System.out.println("Block Mined!!! : " + hashStr);
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34
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35
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36
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37 }
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38
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39 public boolean increment(byte[] bytes) {
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40 final int startIndex = 0;
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41 int i;
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42 for (i = bytes.length - 1; i >= startIndex; i--) {
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43 bytes[i]++;
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44 if (bytes[i] != 0)
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45 break;
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46 }
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47
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48 return (i >= startIndex || bytes[startIndex] != 0);
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49 }
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50
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51 public int compareTo(byte[] buffer1, int offset1, int length1,
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52 byte[] buffer2, int offset2, int length2) {
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53 // Short circuit equal case
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54 if (buffer1 == buffer2 &&
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55 offset1 == offset2 &&
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56 length1 == length2) {
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57 return 0;
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58 }
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59 int end1 = offset1 + length1;
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60 int end2 = offset2 + length2;
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61 for (int i = offset1, j = offset2; i < end1 && j < end2; i++, j++) {
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62 int a = (buffer1[i] & 0xff);
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63 int b = (buffer2[j] & 0xff);
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64 if (a != b) {
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65 return a - b;
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66 }
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67 }
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68 return length1 - length2;
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69 }
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70 }
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