How to use

ECPrivateKey

in

java.security.interfaces

RawECPrivateKey(final ECPrivateKey original) {
  super(original);
  s = original.getS();
  params = original.getParams();

@Override
public String getAlgorithm() {
  return this.getKey().getAlgorithm();

@Override
public byte[] getEncoded() {
  return this.getKey().getEncoded();

  return (T) new ECPublicKeySpec(ecKey.getW(), ecKey.getParams());
} else if (key instanceof PublicKey && ECPublicKeySpec.class.isAssignableFrom(keySpec)) {
  final byte[] encoded = key.getEncoded();
  return (T) new ECPublicKeySpec(ecKey.getW(), ecKey.getParams());
} else if (key instanceof ECPrivateKey
    && ECPrivateKeySpec.class.isAssignableFrom(keySpec)) {
  ECPrivateKey ecKey = (ECPrivateKey) key;
  return (T) new ECPrivateKeySpec(ecKey.getS(), ecKey.getParams());
} else if (key instanceof PrivateKey && ECPrivateKeySpec.class.isAssignableFrom(keySpec)) {
  final byte[] encoded = key.getEncoded();
  return (T) new ECPrivateKeySpec(ecKey.getS(), ecKey.getParams());
} else if (key instanceof PrivateKey
    && PKCS8EncodedKeySpec.class.isAssignableFrom(keySpec)) {

public void init(int key_size) throws Exception {
 String name=null;
 if(key_size==256) name="secp256r1";
 else if(key_size==384) name="secp384r1";
 else if(key_size==521) name="secp521r1";
 else throw new JSchException("unsupported key size: "+key_size);
 for(int i = 0; i<1000; i++) {
  KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC");
  ECGenParameterSpec ecsp = new ECGenParameterSpec(name);
  kpg.initialize(ecsp);
  KeyPair kp = kpg.genKeyPair();
  prvKey = (ECPrivateKey)kp.getPrivate();
  pubKey = (ECPublicKey)kp.getPublic();
  params=pubKey.getParams();
  d=((ECPrivateKey)prvKey).getS().toByteArray();
  ECPoint w = pubKey.getW();
  r = w.getAffineX().toByteArray();
  s = w.getAffineY().toByteArray();
  if(r.length!=s.length) continue;
  if(key_size==256 && r.length==32) break;
  if(key_size==384 && r.length==48) break;
  if(key_size==521 && r.length==66) break;
 if(d.length<r.length){
  d=insert0(d);
public byte[] getD(){return d;}

public BCECPrivateKey(
  ECPrivateKey key,
  ProviderConfiguration configuration)
  this.d = key.getS();
  this.algorithm = key.getAlgorithm();
  this.ecSpec = key.getParams();
  this.configuration = configuration;

    
ECPrivateKey ecPrivateKey = (ECPrivateKey)privateKey;
 System.out.println(ecPrivateKey.getS().toByteArray().length);
 ECPublicKey ecPublicKey = (ECPublicKey)publicKey;
 System.out.println(ecPublicKey.getW().getAffineX().toByteArray().length + ecPublicKey.getW().getAffineY().toByteArray().length);

private




    
 static ECParameterSpec getECParameterSpec(String curve, boolean isPrivate)
  throws Exception {
  KeyPair pair = generateECKeyPair(curve);
  return isPrivate ? ((ECPublicKey) pair.getPublic()).getParams()
    : ((ECPrivateKey) pair.getPrivate()).getParams();

/**
 * Checks that the public key's params is the same as the private key's params, and the public key
 * is a valid point on the private key's curve.
 * @since 1.1.0
public static void validatePublicKey(ECPublicKey publicKey, ECPrivateKey privateKey)
  throws GeneralSecurityException {
 validatePublicKeySpec(publicKey, privateKey);
 checkPointOnCurve(publicKey.getW(), privateKey.getParams().getCurve());

@Override





    
public BigInteger getS() {
  return this.getKey().getS();

AlgorithmParameterSpec spec = k.getParams();
SigType type;
if (spec.equals(SigType.ECDSA_SHA256_P256.getParams()))

if (k.getParams() != null)
  return new java.security.spec.ECPublicKeySpec(k.getW(), k.getParams());
if (k.getParams() != null)
  return new java.security.spec.ECPrivateKeySpec(k.getS(), k.getParams());
  return 




    
new java.security.spec.ECPrivateKeySpec(k.getS(), EC5Util.convertSpec(EC5Util.convertCurve(implicitSpec.getCurve(), implicitSpec.getSeed()), implicitSpec)); 
if (k.getParams() != null)
  return new com.bugvm.bouncycastle.jce.spec.ECPrivateKeySpec(k.getS(), EC5Util.convertSpec(k.getParams(), false));
  return new com.bugvm.bouncycastle.jce.spec.ECPrivateKeySpec(k.getS(), implicitSpec);

public void init(int key_size) throws Exception {
 String name=null;
 if(key_size==256) name="secp256r1";
 else if(key_size==384) name="secp384r1";
 else if(key_size==521) name="secp521r1";
 else throw new JSchException("unsupported key size: "+key_size);
 for(int i = 0; i<1000; i++) {
  KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC");
  ECGenParameterSpec ecsp = new ECGenParameterSpec(name);
  kpg.initialize(ecsp);
  KeyPair kp = kpg.genKeyPair();
  prvKey = (ECPrivateKey)kp.getPrivate();
  pubKey = (ECPublicKey)kp.getPublic();
  params=pubKey.getParams();
  d=((ECPrivateKey)prvKey).getS().toByteArray();
  ECPoint w = pubKey.getW();
  r = w.getAffineX().toByteArray();
  s = w.getAffineY().toByteArray();
  if(r.length!=s.length) continue;
  if(key_size==256 && r.length==32) break;
  if(key_size==384 && r.length==48) break;
  if(key_size==521 && r.length==66) break;
 if(d.length<r.length){
  d=insert0(d);
public byte[] getD(){return d;}

public BCECPrivateKey(
  ECPrivateKey key,
  ProviderConfiguration configuration)
  this.d = key.getS();
  this.algorithm = key.getAlgorithm();
  this.ecSpec = key.getParams();
  this.configuration = configuration;

writeToStream(privateKeyBytes, 0, ecPrivateKey.getS(), PRIVATE_KEY_LENGTH);
ECPoint ecPoint = ecPublicKey.getW();

private




    
 static ECParameterSpec getECParameterSpec(String curve, boolean isPrivate)
  throws Exception {
  KeyPair pair = generateECKeyPair(curve);
  return isPrivate ? ((ECPublicKey) pair.getPublic()).getParams()
    : ((ECPrivateKey) pair.getPrivate()).getParams();

private void checkPointIsOnCurve(ECPublicKey ephemeralPublicKey, ECPrivateKey privateKey) throws JoseException
  // to prevent 'Invalid Curve Attack': for NIST curves, check whether public key is on the private key's curve.
  // from https://www.cs.bris.ac.uk/Research/CryptographySecurity/RWC/2017/nguyen.quan.pdf
  // there appear to be similar checks in the JVM starting with 1.8.0_51 but
  // doing it here explicitly seems prudent
  // (y^2) mod p = (x^3 + ax + b) mod p
  // thanks to Antonio Sanso for guidance on how to do this check
  ECParameterSpec ecParameterSpec = privateKey.getParams();
  EllipticCurve curve = ecParameterSpec.getCurve();
  ECPoint point = ephemeralPublicKey.getW();
  BigInteger x = point.getAffineX();
  BigInteger y = point.getAffineY();
  BigInteger a = curve.getA();
  BigInteger b = curve.getB();
  BigInteger p = ((ECFieldFp) curve.getField()).getP();
  BigInteger leftSide = (y.pow(2)).mod(p);
  BigInteger rightSide = (x.pow(




    
3).add(a.multiply(x)).add(b)).mod(p);
  boolean onCurve = leftSide.equals(rightSide);
  if (!onCurve)
    throw new JoseException(HeaderParameterNames.EPHEMERAL_PUBLIC_KEY + " is invalid for " + EllipticCurves.getName(curve));

public




    
 static SigningPrivateKey fromJavaKey(ECPrivateKey pk, SigType type)
             throws GeneralSecurityException {
  BigInteger s = pk.getS();
  int len = type.getPrivkeyLen();
  byte[] bs = rectify(s, len);
  return new SigningPrivateKey(type, bs);

static OpenSSLKey wrapPlatformKey(ECPrivateKey ecPrivateKey) throws InvalidKeyException {
  OpenSSLECGroupContext group;
  try {
    group = OpenSSLECGroupContext.getInstance(ecPrivateKey.getParams());
  } catch (InvalidAlgorithmParameterException e) {
    throw new InvalidKeyException("Unknown group parameters", e);
  




    
return wrapPlatformKey(ecPrivateKey, group);

if




    
 (k.getParams() != null)
  return new java.security.spec.ECPublicKeySpec(k.getW(), k.getParams());
if (k.getParams() != null)
  return new java.security.spec.ECPrivateKeySpec(k.getS(), k.getParams());
  return new java.security.spec.ECPrivateKeySpec(k.getS(), EC5Util.convertSpec(EC5Util.convertCurve(implicitSpec.getCurve(), implicitSpec.getSeed()), implicitSpec));
if (k.getParams() != null)
  return new org.ripple.bouncycastle.jce.spec.ECPrivateKeySpec(k.getS(), EC5Util.convertSpec(k.getParams(), false));
  return new org.ripple.bouncycastle.jce.spec.ECPrivateKeySpec(k.getS(), implicitSpec);