Java tutorial
package org.bouncycastle.jce.provider; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.math.BigInteger; import java.security.interfaces.ECPublicKey; import java.security.spec.ECParameterSpec; import java.security.spec.ECPoint; import java.security.spec.ECPublicKeySpec; import java.security.spec.EllipticCurve; import org.bouncycastle.asn1.ASN1Encodable; import org.bouncycastle.asn1.ASN1ObjectIdentifier; import org.bouncycastle.asn1.ASN1OctetString; import org.bouncycastle.asn1.ASN1Primitive; import org.bouncycastle.asn1.DERBitString; import org.bouncycastle.asn1.DERNull; import org.bouncycastle.asn1.DEROctetString; import org.bouncycastle.asn1.cryptopro.CryptoProObjectIdentifiers; import org.bouncycastle.asn1.cryptopro.ECGOST3410NamedCurves; import org.bouncycastle.asn1.cryptopro.GOST3410PublicKeyAlgParameters; import org.bouncycastle.asn1.x509.AlgorithmIdentifier; import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo; import org.bouncycastle.asn1.x9.X962Parameters; import org.bouncycastle.asn1.x9.X9ECParameters; import org.bouncycastle.asn1.x9.X9ECPoint; import org.bouncycastle.asn1.x9.X9IntegerConverter; import org.bouncycastle.asn1.x9.X9ObjectIdentifiers; import org.bouncycastle.crypto.params.ECDomainParameters; import org.bouncycastle.crypto.params.ECPublicKeyParameters; import org.bouncycastle.jcajce.provider.asymmetric.util.EC5Util; import org.bouncycastle.jcajce.provider.asymmetric.util.ECUtil; import org.bouncycastle.jcajce.provider.asymmetric.util.KeyUtil; import org.bouncycastle.jce.ECGOST3410NamedCurveTable; import org.bouncycastle.jce.interfaces.ECPointEncoder; import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec; import org.bouncycastle.jce.spec.ECNamedCurveSpec; import org.bouncycastle.math.ec.ECCurve; import org.bouncycastle.util.Strings; public class JCEECPublicKey implements ECPublicKey, org.bouncycastle.jce.interfaces.ECPublicKey, ECPointEncoder { private String algorithm = "EC"; private org.bouncycastle.math.ec.ECPoint q; private ECParameterSpec ecSpec; private boolean withCompression; private GOST3410PublicKeyAlgParameters gostParams; public JCEECPublicKey(String algorithm, JCEECPublicKey key) { this.algorithm = algorithm; this.q = key.q; this.ecSpec = key.ecSpec; this.withCompression = key.withCompression; this.gostParams = key.gostParams; } public JCEECPublicKey(String algorithm, ECPublicKeySpec spec) { this.algorithm = algorithm; this.ecSpec = spec.getParams(); this.q = EC5Util.convertPoint(ecSpec, spec.getW()); } public JCEECPublicKey(String algorithm, org.bouncycastle.jce.spec.ECPublicKeySpec spec) { this.algorithm = algorithm; this.q = spec.getQ(); if (spec.getParams() != null) // can be null if implictlyCa { ECCurve curve = spec.getParams().getCurve(); EllipticCurve ellipticCurve = EC5Util.convertCurve(curve, spec.getParams().getSeed()); this.ecSpec = EC5Util.convertSpec(ellipticCurve, spec.getParams()); } else { if (q.getCurve() == null) { org.bouncycastle.jce.spec.ECParameterSpec s = BouncyCastleProvider.CONFIGURATION .getEcImplicitlyCa(); q = s.getCurve().createPoint(q.getAffineXCoord().toBigInteger(), q.getAffineYCoord().toBigInteger()); } this.ecSpec = null; } } public JCEECPublicKey(String algorithm, ECPublicKeyParameters params, ECParameterSpec spec) { ECDomainParameters dp = params.getParameters(); this.algorithm = algorithm; this.q = params.getQ(); if (spec == null) { EllipticCurve ellipticCurve = EC5Util.convertCurve(dp.getCurve(), dp.getSeed()); this.ecSpec = createSpec(ellipticCurve, dp); } else { this.ecSpec = spec; } } public JCEECPublicKey(String algorithm, ECPublicKeyParameters params, org.bouncycastle.jce.spec.ECParameterSpec spec) { ECDomainParameters dp = params.getParameters(); this.algorithm = algorithm; this.q = params.getQ(); if (spec == null) { EllipticCurve ellipticCurve = EC5Util.convertCurve(dp.getCurve(), dp.getSeed()); this.ecSpec = createSpec(ellipticCurve, dp); } else { EllipticCurve ellipticCurve = EC5Util.convertCurve(spec.getCurve(), spec.getSeed()); this.ecSpec = EC5Util.convertSpec(ellipticCurve, spec); } } /* * called for implicitCA */ public JCEECPublicKey(String algorithm, ECPublicKeyParameters params) { this.algorithm = algorithm; this.q = params.getQ(); this.ecSpec = null; } private ECParameterSpec createSpec(EllipticCurve ellipticCurve, ECDomainParameters dp) { return new ECParameterSpec(ellipticCurve, EC5Util.convertPoint(dp.getG()), dp.getN(), dp.getH().intValue()); } public JCEECPublicKey(ECPublicKey key) { this.algorithm = key.getAlgorithm(); this.ecSpec = key.getParams(); this.q = EC5Util.convertPoint(this.ecSpec, key.getW()); } JCEECPublicKey(SubjectPublicKeyInfo info) { populateFromPubKeyInfo(info); } private void populateFromPubKeyInfo(SubjectPublicKeyInfo info) { AlgorithmIdentifier algID = info.getAlgorithm(); if (algID.getAlgorithm().equals(CryptoProObjectIdentifiers.gostR3410_2001)) { DERBitString bits = info.getPublicKeyData(); ASN1OctetString key; this.algorithm = "ECGOST3410"; try { key = (ASN1OctetString) ASN1Primitive.fromByteArray(bits.getBytes()); } catch (IOException ex) { throw new IllegalArgumentException("error recovering public key"); } byte[] keyEnc = key.getOctets(); byte[] x9Encoding = new byte[65]; x9Encoding[0] = 0x04; for (int i = 1; i <= 32; ++i) { x9Encoding[i] = keyEnc[32 - i]; x9Encoding[i + 32] = keyEnc[64 - i]; } gostParams = GOST3410PublicKeyAlgParameters.getInstance(algID.getParameters()); ECNamedCurveParameterSpec spec = ECGOST3410NamedCurveTable .getParameterSpec(ECGOST3410NamedCurves.getName(gostParams.getPublicKeyParamSet())); ECCurve curve = spec.getCurve(); EllipticCurve ellipticCurve = EC5Util.convertCurve(curve, spec.getSeed()); this.q = curve.decodePoint(x9Encoding); ecSpec = new ECNamedCurveSpec(ECGOST3410NamedCurves.getName(gostParams.getPublicKeyParamSet()), ellipticCurve, EC5Util.convertPoint(spec.getG()), spec.getN(), spec.getH()); } else { X962Parameters params = X962Parameters.getInstance(algID.getParameters()); ECCurve curve; EllipticCurve ellipticCurve; if (params.isNamedCurve()) { ASN1ObjectIdentifier oid = (ASN1ObjectIdentifier) params.getParameters(); X9ECParameters ecP = ECUtil.getNamedCurveByOid(oid); curve = ecP.getCurve(); ellipticCurve = EC5Util.convertCurve(curve, ecP.getSeed()); ecSpec = new ECNamedCurveSpec(ECUtil.getCurveName(oid), ellipticCurve, EC5Util.convertPoint(ecP.getG()), ecP.getN(), ecP.getH()); } else if (params.isImplicitlyCA()) { ecSpec = null; curve = BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa().getCurve(); } else { X9ECParameters ecP = X9ECParameters.getInstance(params.getParameters()); curve = ecP.getCurve(); ellipticCurve = EC5Util.convertCurve(curve, ecP.getSeed()); this.ecSpec = new ECParameterSpec(ellipticCurve, EC5Util.convertPoint(ecP.getG()), ecP.getN(), ecP.getH().intValue()); } DERBitString bits = info.getPublicKeyData(); byte[] data = bits.getBytes(); ASN1OctetString key = new DEROctetString(data); // // extra octet string - one of our old certs... // if (data[0] == 0x04 && data[1] == data.length - 2 && (data[2] == 0x02 || data[2] == 0x03)) { int qLength = new X9IntegerConverter().getByteLength(curve); if (qLength >= data.length - 3) { try { key = (ASN1OctetString) ASN1Primitive.fromByteArray(data); } catch (IOException ex) { throw new IllegalArgumentException("error recovering public key"); } } } X9ECPoint derQ = new X9ECPoint(curve, key); this.q = derQ.getPoint(); } } public String getAlgorithm() { return algorithm; } public String getFormat() { return "X.509"; } public byte[] getEncoded() { ASN1Encodable params; SubjectPublicKeyInfo info; if (algorithm.equals("ECGOST3410")) { if (gostParams != null) { params = gostParams; } else { if (ecSpec instanceof ECNamedCurveSpec) { params = new GOST3410PublicKeyAlgParameters( ECGOST3410NamedCurves.getOID(((ECNamedCurveSpec) ecSpec).getName()), CryptoProObjectIdentifiers.gostR3411_94_CryptoProParamSet); } else { // strictly speaking this may not be applicable... ECCurve curve = EC5Util.convertCurve(ecSpec.getCurve()); X9ECParameters ecP = new X9ECParameters(curve, new X9ECPoint(EC5Util.convertPoint(curve, ecSpec.getGenerator()), withCompression), ecSpec.getOrder(), BigInteger.valueOf(ecSpec.getCofactor()), ecSpec.getCurve().getSeed()); params = new X962Parameters(ecP); } } BigInteger bX = this.q.getAffineXCoord().toBigInteger(); BigInteger bY = this.q.getAffineYCoord().toBigInteger(); byte[] encKey = new byte[64]; extractBytes(encKey, 0, bX); extractBytes(encKey, 32, bY); try { info = new SubjectPublicKeyInfo( new AlgorithmIdentifier(CryptoProObjectIdentifiers.gostR3410_2001, params), new DEROctetString(encKey)); } catch (IOException e) { return null; } } else { if (ecSpec instanceof ECNamedCurveSpec) { ASN1ObjectIdentifier curveOid = ECUtil.getNamedCurveOid(((ECNamedCurveSpec) ecSpec).getName()); if (curveOid == null) { curveOid = new ASN1ObjectIdentifier(((ECNamedCurveSpec) ecSpec).getName()); } params = new X962Parameters(curveOid); } else if (ecSpec == null) { params = new X962Parameters(DERNull.INSTANCE); } else { ECCurve curve = EC5Util.convertCurve(ecSpec.getCurve()); X9ECParameters ecP = new X9ECParameters(curve, new X9ECPoint(EC5Util.convertPoint(curve, ecSpec.getGenerator()), withCompression), ecSpec.getOrder(), BigInteger.valueOf(ecSpec.getCofactor()), ecSpec.getCurve().getSeed()); params = new X962Parameters(ecP); } byte[] pubKeyOctets = this.getQ().getEncoded(withCompression); info = new SubjectPublicKeyInfo(new AlgorithmIdentifier(X9ObjectIdentifiers.id_ecPublicKey, params), pubKeyOctets); } return KeyUtil.getEncodedSubjectPublicKeyInfo(info); } private void extractBytes(byte[] encKey, int offSet, BigInteger bI) { byte[] val = bI.toByteArray(); if (val.length < 32) { byte[] tmp = new byte[32]; System.arraycopy(val, 0, tmp, tmp.length - val.length, val.length); val = tmp; } for (int i = 0; i != 32; i++) { encKey[offSet + i] = val[val.length - 1 - i]; } } public ECParameterSpec getParams() { return ecSpec; } public org.bouncycastle.jce.spec.ECParameterSpec getParameters() { if (ecSpec == null) // implictlyCA { return null; } return EC5Util.convertSpec(ecSpec); } public ECPoint getW() { return EC5Util.convertPoint(q); } public org.bouncycastle.math.ec.ECPoint getQ() { if (ecSpec == null) { return q.getDetachedPoint(); } return q; } public org.bouncycastle.math.ec.ECPoint engineGetQ() { return q; } org.bouncycastle.jce.spec.ECParameterSpec engineGetSpec() { if (ecSpec != null) { return EC5Util.convertSpec(ecSpec); } return BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa(); } public String toString() { StringBuffer buf = new StringBuffer(); String nl = Strings.lineSeparator(); buf.append("EC Public Key").append(nl); buf.append(" X: ").append(this.q.getAffineXCoord().toBigInteger().toString(16)).append(nl); buf.append(" Y: ").append(this.q.getAffineYCoord().toBigInteger().toString(16)).append(nl); return buf.toString(); } public void setPointFormat(String style) { withCompression = !("UNCOMPRESSED".equalsIgnoreCase(style)); } public boolean equals(Object o) { if (!(o instanceof JCEECPublicKey)) { return false; } JCEECPublicKey other = (JCEECPublicKey) o; return engineGetQ().equals(other.engineGetQ()) && (engineGetSpec().equals(other.engineGetSpec())); } public int hashCode() { return engineGetQ().hashCode() ^ engineGetSpec().hashCode(); } private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { byte[] enc = (byte[]) in.readObject(); populateFromPubKeyInfo(SubjectPublicKeyInfo.getInstance(ASN1Primitive.fromByteArray(enc))); this.algorithm = (String) in.readObject(); this.withCompression = in.readBoolean(); } private void writeObject(ObjectOutputStream out) throws IOException { out.writeObject(this.getEncoded()); out.writeObject(algorithm); out.writeBoolean(withCompression); } }