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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.asn1.sec.SECNamedCurves;
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4 import org.bouncycastle.asn1.x9.X9ECParameters;
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5 import org.bouncycastle.crypto.params.ECDomainParameters;
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6 import org.bouncycastle.jce.provider.BouncyCastleProvider;
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7 import org.bouncycastle.jce.spec.ECParameterSpec;
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8 import org.bouncycastle.math.ec.ECPoint;
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9
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10 import java.math.BigInteger;
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11 import java.security.*;
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12 import java.security.interfaces.ECPublicKey;
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13 import java.security.spec.ECGenParameterSpec;
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14
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15
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16 public class ECKey {
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17
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18 public static final ECDomainParameters CURVE;
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19 public static final ECParameterSpec CURVE_SPEC;
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20
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21 public static final BigInteger HALF_CURVE_ORDER;
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22 private static final SecureRandom secureRandom;
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23
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24 private final PrivateKey privateKey;
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25 private final PublicKey publicKey;
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26 private final Provider provider;
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27
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28 static {
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29 X9ECParameters params = SECNamedCurves.getByName("secp256k1");
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30 CURVE = new ECDomainParameters(params.getCurve(), params.getG(), params.getN(), params.getH());
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31 CURVE_SPEC = new ECParameterSpec(params.getCurve(), params.getG(), params.getN(), params.getH());
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32 HALF_CURVE_ORDER = params.getN().shiftRight(1);
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33 secureRandom = new SecureRandom();
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34 }
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35
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36 public ECKey() {
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37 this(secureRandom);
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38 }
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39
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40 public ECKey(SecureRandom secureRandom) {
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41 this(new BouncyCastleProvider(), secureRandom);
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42 }
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43
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44
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45 public ECKey(Provider provider, SecureRandom secureRandom) {
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46 this.provider = provider;
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47
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48 KeyPairGenerator keyGen;
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49 try {
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50 keyGen = KeyPairGenerator.getInstance("EC");
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51 ECGenParameterSpec SECP256K1_CURVE = new ECGenParameterSpec("secp256k1");
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52 keyGen.initialize(SECP256K1_CURVE);
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53 } catch (NoSuchAlgorithmException ex) {
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54 throw new AssertionError(ex);
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55 } catch (InvalidAlgorithmParameterException ex) {
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56 throw new AssertionError(ex);
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57 }
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58
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59 KeyPair keyPair = keyGen.generateKeyPair();
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60
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61 this.privateKey = keyPair.getPrivate();
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62 this.publicKey = keyPair.getPublic();
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63
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64 }
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65
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66 private static ECPoint extractPublicKey(final ECPublicKey ecPublicKey) {
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67 final java.security.spec.ECPoint publicPointW = ecPublicKey.getW();
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68 final BigInteger xCoord = publicPointW.getAffineX();
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69 final BigInteger yCoord = publicPointW.getAffineY();
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70
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71 return CURVE.getCurve().createPoint(xCoord, yCoord);
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72 }
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73
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74 public byte[] applyECDSASig(byte[] input) {
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75 Signature dsa;
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76 byte[] output;
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77
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78 if (privateKey == null)
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79 throw new RuntimeException();
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80 try {
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81 dsa = Signature.getInstance("ECDSA", "BC");
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82 dsa.initSign(privateKey);
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83 dsa.update(input);
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84 output = dsa.sign();
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85 } catch (Exception e) {
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86 throw new RuntimeException(e);
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87 }
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88 return output;
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89 }
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90
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91 public static boolean verifyECDSASig(byte[] data, byte[] signature, PublicKey publicKey) {
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92 try {
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93 Signature ecdsaVerify = Signature.getInstance("ECDSA", "BC");
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94 ecdsaVerify.initVerify(publicKey);
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95 ecdsaVerify.update(data);
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96 return ecdsaVerify.verify(signature);
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97 }catch(Exception e) {
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98 throw new RuntimeException(e);
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99 }
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100 }
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101
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102 }
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