Java ECPoint類代碼示例

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
public static byte[] decrypt(BigInteger privKey, byte[] cipher, byte[] macData) throws IOException, InvalidCipherTextException {

        byte[] plaintext;

        ByteArrayInputStream is = new ByteArrayInputStream(cipher);
        byte[] ephemBytes = new byte[2*((CURVE.getCurve().getFieldSize()+7)/8) + 1];

        is.read(ephemBytes);
        ECPoint ephem = CURVE.getCurve().decodePoint(ephemBytes);
        byte[] IV = new byte[KEY_SIZE /8];
        is.read(IV);
        byte[] cipherBody = new byte[is.available()];
        is.read(cipherBody);

        plaintext = decrypt(ephem, privKey, IV, cipherBody, macData);

        return plaintext;
    }
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
private static ECPoint byteArrayToECPoint(final byte[] value, final ECCurve.Fp curve)
		throws IllegalArgumentException {
	final byte[] x = new byte[(value.length - 1) / 2];
	final byte[] y = new byte[(value.length - 1) / 2];
	if (value[0] != (byte) 0x04) {
		throw new IllegalArgumentException("No uncompressed Point found!"); //$NON-NLS-1$
	}
	System.arraycopy(value, 1, x, 0, (value.length - 1) / 2);
	System.arraycopy(value, 1 + (value.length - 1) / 2, y, 0,
			(value.length - 1) / 2);
	final ECFieldElement.Fp xE = (org.spongycastle.math.ec.ECFieldElement.Fp) curve.fromBigInteger(new BigInteger(1, x));
	final ECFieldElement.Fp yE = (org.spongycastle.math.ec.ECFieldElement.Fp) curve.fromBigInteger(new BigInteger(1, y));

	final ECPoint point = curve.createPoint(xE.toBigInteger(), yE.toBigInteger());
	return point;
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
private static EthereumIESEngine makeIESEngine(boolean isEncrypt, ECPoint pub, BigInteger prv, byte[] IV) {
    AESFastEngine aesFastEngine = new AESFastEngine();

    EthereumIESEngine iesEngine = new EthereumIESEngine(
            new ECDHBasicAgreement(),
            new ConcatKDFBytesGenerator(new SHA256Digest()),
            new HMac(new SHA256Digest()),
            new SHA256Digest(),
            new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));


    byte[]         d = new byte[] {};
    byte[]         e = new byte[] {};

    IESParameters p = new IESWithCipherParameters(d, e, KEY_SIZE, KEY_SIZE);
    ParametersWithIV parametersWithIV = new ParametersWithIV(p, IV);

    iesEngine.init(isEncrypt, new ECPrivateKeyParameters(prv, curve), new ECPublicKeyParameters(pub, curve), parametersWithIV);
    return iesEngine;
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
public static byte[] decrypt(ECPoint ephem, BigInteger prv, byte[] iv, byte[] cipher, byte[] macData) throws InvalidCipherTextException {
    AESFastEngine aesFastEngine = new AESFastEngine();

    EthereumIESEngine iesEngine = new EthereumIESEngine(
            new ECDHBasicAgreement(),
            new ConcatKDFBytesGenerator(new SHA256Digest()),
            new HMac(new SHA256Digest()),
            new SHA256Digest(),
            new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));


    byte[]         d = new byte[] {};
    byte[]         e = new byte[] {};

    IESParameters p = new IESWithCipherParameters(d, e, KEY_SIZE, KEY_SIZE);
    ParametersWithIV parametersWithIV =
            new ParametersWithIV(p, iv);

    iesEngine.init(false, new ECPrivateKeyParameters(prv, CURVE), new ECPublicKeyParameters(ephem, CURVE), parametersWithIV);

    return iesEngine.processBlock(cipher, 0, cipher.length, macData);
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
private static EthereumIESEngine makeIESEngine(boolean isEncrypt, ECPoint pub, BigInteger prv, byte[] iv) {
    AESFastEngine aesFastEngine = new AESFastEngine();

    EthereumIESEngine iesEngine = new EthereumIESEngine(
            new ECDHBasicAgreement(),
            new ConcatKDFBytesGenerator(new SHA256Digest()),
            new HMac(new SHA256Digest()),
            new SHA256Digest(),
            new BufferedBlockCipher(new SICBlockCipher(aesFastEngine)));


    byte[]         d = new byte[] {};
    byte[]         e = new byte[] {};

    IESParameters p = new IESWithCipherParameters(d, e, KEY_SIZE, KEY_SIZE);
    ParametersWithIV parametersWithIV = new ParametersWithIV(p, iv);

    iesEngine.init(isEncrypt, new ECPrivateKeyParameters(prv, CURVE), new ECPublicKeyParameters(pub, CURVE), parametersWithIV);
    return iesEngine;
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
/**
 * Pair a private key with a public EC point.
 *
 * All private key operations will use the provider.
 */
public ECKey(Provider provider, @Nullable PrivateKey privKey, ECPoint pub) {
    this.provider = provider;

    if (privKey == null || isECPrivateKey(privKey)) {
        this.privKey = privKey;
    } else {
        throw new IllegalArgumentException(
            "Expected EC private key, given a private key object with class " +
            privKey.getClass().toString() +
            " and algorithm " + privKey.getAlgorithm());
    }

    if (pub == null) {
        throw new IllegalArgumentException("Public key may not be null");
    } else {
        this.pub = pub;
    }
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
/**
 * Creates an ECKey given either the private key only, the public key only, or both. If only the private key
 * is supplied, the public key will be calculated from it (this is slow). If both are supplied, it's assumed
 * the public key already correctly matches the private key. If only the public key is supplied, this ECKey cannot
 * be used for signing.
 * @param compressed If set to true and pubKey is null, the derived public key will be in compressed form.
 */
@Deprecated
public ECKey(@Nullable BigInteger privKey, @Nullable byte[] pubKey, boolean compressed) {
    if (privKey == null && pubKey == null)
        throw new IllegalArgumentException("ECKey requires at least private or public key");
    this.priv = privKey;
    if (pubKey == null) {
        // Derive public from private.
        ECPoint point = publicPointFromPrivate(privKey);
        point = getPointWithCompression(point, compressed);
        this.pub = new LazyECPoint(point);
    } else {
        // We expect the pubkey to be in regular encoded form, just as a BigInteger. Therefore the first byte is
        // a special marker byte.
        // TODO: This is probably not a useful API and may be confusing.
        this.pub = new LazyECPoint(CURVE.getCurve(), pubKey);
    }
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
private static ECPoint extractPublicKey(final ECPublicKey ecPublicKey) {
    final java.security.spec.ECPoint publicPointW = ecPublicKey.getW();
    final BigInteger xCoord = publicPointW.getAffineX();
    final BigInteger yCoord = publicPointW.getAffineY();

    return CURVE.getCurve().createPoint(xCoord, yCoord);
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
/**
 * Pair a private key integer with a public EC point
 *
 * BouncyCastle will be used as the Java Security Provider
 */
public ECKey(@Nullable BigInteger priv, ECPoint pub) {
    this(
            SpongyCastleProvider.getInstance(),
            privateKeyFromBigInteger(priv),
            pub
    );
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
private static ECPoint extractPublicKey(ECPublicKey ecPublicKey) {
  java.security.spec.ECPoint publicPointW = ecPublicKey.getW();
  BigInteger xCoord = publicPointW.getAffineX();
  BigInteger yCoord = publicPointW.getAffineY();

  return CURVE.getCurve()
      .createPoint(xCoord, yCoord);
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
@Test
public void testRoundTrip() throws InvalidCipherTextException, IOException {
    ECPoint pub1 = pub(PRIVATE_KEY1);
    byte[] plaintext = "Hello world".getBytes();
    byte[] ciphertext = encrypt(pub1, plaintext);
    byte[] plaintext1 = decrypt(PRIVATE_KEY1, ciphertext);
    assertArrayEquals(plaintext, plaintext1);
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
public EncryptionHandshake(ECPoint remotePublicKey) {
    this.remotePublicKey = remotePublicKey;
    ephemeralKey = new ECKey(random);
    initiatorNonce = new byte[NONCE_SIZE];
    random.nextBytes(initiatorNonce);
    isInitiator = true;
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
public DeterministicKey(ImmutableList<ChildNumber> childNumberPath,
                        byte[] chainCode,
                        ECPoint publicAsPoint,
                        @Nullable BigInteger priv,
                        @Nullable DeterministicKey parent) {
    this(childNumberPath, chainCode, new LazyECPoint(publicAsPoint), priv, parent);
}
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
public static byte[] encrypt(ECPoint toPub, byte[] plaintext) throws InvalidCipherTextException, IOException {

        ECKeyPairGenerator eGen = new ECKeyPairGenerator();
        SecureRandom random = new SecureRandom();
        KeyGenerationParameters gParam = new ECKeyGenerationParameters(curve, random);

        eGen.init(gParam);

        byte[] IV = new byte[KEY_SIZE/8];
        new SecureRandom().nextBytes(IV);

        AsymmetricCipherKeyPair ephemPair = eGen.generateKeyPair();
        BigInteger prv = ((ECPrivateKeyParameters)ephemPair.getPrivate()).getD();
        ECPoint pub = ((ECPublicKeyParameters)ephemPair.getPublic()).getQ();
        EthereumIESEngine iesEngine = makeIESEngine(true, toPub, prv, IV);


        ECKeyGenerationParameters keygenParams = new ECKeyGenerationParameters(curve, random);
        ECKeyPairGenerator generator = new ECKeyPairGenerator();
        generator.init(keygenParams);

        ECKeyPairGenerator gen = new ECKeyPairGenerator();
        gen.init(new ECKeyGenerationParameters(ECKey.CURVE, random));

        byte[] cipher = iesEngine.processBlock(plaintext, 0, plaintext.length);
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        bos.write(pub.getEncoded(false));
        bos.write(IV);
        bos.write(cipher);
        return bos.toByteArray();
    }
 

import org.spongycastle.math.ec.ECPoint; //導入依賴的package包/類
/**
 * Pair a private key integer with a public EC point
 *
 * BouncyCastle will be used as the Java Security Provider
 */
public ECKey(@Nullable BigInteger priv, ECPoint pub) {
    this(
        SpongyCastleProvider.getInstance(),
        privateKeyFromBigInteger(priv),
        pub
    );
}