Java tutorial
package org.bouncycastle.jcajce.provider.asymmetric.ecgost; 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.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.crypto.params.ECDomainParameters; import org.bouncycastle.crypto.params.ECGOST3410Parameters; 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.jcajce.provider.config.ProviderConfiguration; import org.bouncycastle.jce.ECGOST3410NamedCurveTable; import org.bouncycastle.jce.interfaces.ECPointEncoder; import org.bouncycastle.jce.provider.BouncyCastleProvider; import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec; import org.bouncycastle.jce.spec.ECNamedCurveSpec; import org.bouncycastle.math.ec.ECCurve; public class BCECGOST3410PublicKey implements ECPublicKey, org.bouncycastle.jce.interfaces.ECPublicKey, ECPointEncoder { static final long serialVersionUID = 7026240464295649314L; private String algorithm = "ECGOST3410"; private boolean withCompression; private transient ECPublicKeyParameters ecPublicKey; private transient ECParameterSpec ecSpec; private transient ASN1Encodable gostParams; public BCECGOST3410PublicKey(BCECGOST3410PublicKey key) { this.ecPublicKey = key.ecPublicKey; this.ecSpec = key.ecSpec; this.withCompression = key.withCompression; this.gostParams = key.gostParams; } public BCECGOST3410PublicKey(ECPublicKeySpec spec) { this.ecSpec = spec.getParams(); this.ecPublicKey = new ECPublicKeyParameters(EC5Util.convertPoint(ecSpec, spec.getW()), EC5Util.getDomainParameters(null, spec.getParams())); } public BCECGOST3410PublicKey(org.bouncycastle.jce.spec.ECPublicKeySpec spec, ProviderConfiguration configuration) { if (spec.getParams() != null) // can be null if implictlyCa { ECCurve curve = spec.getParams().getCurve(); EllipticCurve ellipticCurve = EC5Util.convertCurve(curve, spec.getParams().getSeed()); // this may seem a little long-winded but it's how we pick up the custom curve. this.ecPublicKey = new ECPublicKeyParameters(spec.getQ(), ECUtil.getDomainParameters(configuration, spec.getParams())); this.ecSpec = EC5Util.convertSpec(ellipticCurve, spec.getParams()); } else { org.bouncycastle.jce.spec.ECParameterSpec s = configuration.getEcImplicitlyCa(); this.ecPublicKey = new ECPublicKeyParameters( s.getCurve().createPoint(spec.getQ().getAffineXCoord().toBigInteger(), spec.getQ().getAffineYCoord().toBigInteger()), EC5Util.getDomainParameters(configuration, (ECParameterSpec) null)); this.ecSpec = null; } } public BCECGOST3410PublicKey(String algorithm, ECPublicKeyParameters params, ECParameterSpec spec) { ECDomainParameters dp = params.getParameters(); if (dp instanceof ECGOST3410Parameters) { ECGOST3410Parameters p = (ECGOST3410Parameters) dp; this.gostParams = new GOST3410PublicKeyAlgParameters(p.getPublicKeyParamSet(), p.getDigestParamSet(), p.getEncryptionParamSet()); } this.algorithm = algorithm; this.ecPublicKey = params; if (spec == null) { EllipticCurve ellipticCurve = EC5Util.convertCurve(dp.getCurve(), dp.getSeed()); this.ecSpec = createSpec(ellipticCurve, dp); } else { this.ecSpec = spec; } } public BCECGOST3410PublicKey(String algorithm, ECPublicKeyParameters params, org.bouncycastle.jce.spec.ECParameterSpec spec) { ECDomainParameters dp = params.getParameters(); this.algorithm = algorithm; this.ecPublicKey = params; 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 BCECGOST3410PublicKey(String algorithm, ECPublicKeyParameters params) { this.algorithm = algorithm; this.ecPublicKey = params; this.ecSpec = null; } private ECParameterSpec createSpec(EllipticCurve ellipticCurve, ECDomainParameters dp) { return new ECParameterSpec(ellipticCurve, EC5Util.convertPoint(dp.getG()), dp.getN(), dp.getH().intValue()); } public BCECGOST3410PublicKey(ECPublicKey key) { this.algorithm = key.getAlgorithm(); this.ecSpec = key.getParams(); this.ecPublicKey = new ECPublicKeyParameters(EC5Util.convertPoint(this.ecSpec, key.getW()), EC5Util.getDomainParameters(null, key.getParams())); } BCECGOST3410PublicKey(SubjectPublicKeyInfo info) { populateFromPubKeyInfo(info); } private void populateFromPubKeyInfo(SubjectPublicKeyInfo info) { 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]; } ASN1ObjectIdentifier paramOID; if (info.getAlgorithm().getParameters() instanceof ASN1ObjectIdentifier) { paramOID = ASN1ObjectIdentifier.getInstance(info.getAlgorithm().getParameters()); gostParams = paramOID; } else { GOST3410PublicKeyAlgParameters params = GOST3410PublicKeyAlgParameters .getInstance(info.getAlgorithm().getParameters()); gostParams = params; paramOID = params.getPublicKeyParamSet(); } ECNamedCurveParameterSpec spec = ECGOST3410NamedCurveTable .getParameterSpec(ECGOST3410NamedCurves.getName(paramOID)); ECCurve curve = spec.getCurve(); EllipticCurve ellipticCurve = EC5Util.convertCurve(curve, spec.getSeed()); this.ecPublicKey = new ECPublicKeyParameters(curve.decodePoint(x9Encoding), ECUtil.getDomainParameters(null, spec)); this.ecSpec = new ECNamedCurveSpec(ECGOST3410NamedCurves.getName(paramOID), ellipticCurve, EC5Util.convertPoint(spec.getG()), spec.getN(), spec.getH()); } public String getAlgorithm() { return algorithm; } public String getFormat() { return "X.509"; } public byte[] getEncoded() { ASN1Encodable params; SubjectPublicKeyInfo info; params = getGostParams(); if (params == null) { 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.ecPublicKey.getQ().getAffineXCoord().toBigInteger(); BigInteger bY = this.ecPublicKey.getQ().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; } 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(ecPublicKey.getQ()); } public org.bouncycastle.math.ec.ECPoint getQ() { if (ecSpec == null) { return ecPublicKey.getQ().getDetachedPoint(); } return ecPublicKey.getQ(); } ECPublicKeyParameters engineGetKeyParameters() { return ecPublicKey; } org.bouncycastle.jce.spec.ECParameterSpec engineGetSpec() { if (ecSpec != null) { return EC5Util.convertSpec(ecSpec); } return BouncyCastleProvider.CONFIGURATION.getEcImplicitlyCa(); } public String toString() { return ECUtil.publicKeyToString(algorithm, ecPublicKey.getQ(), engineGetSpec()); } public void setPointFormat(String style) { withCompression = !("UNCOMPRESSED".equalsIgnoreCase(style)); } public boolean equals(Object o) { if (!(o instanceof BCECGOST3410PublicKey)) { return false; } BCECGOST3410PublicKey other = (BCECGOST3410PublicKey) o; return ecPublicKey.getQ().equals(other.ecPublicKey.getQ()) && (engineGetSpec().equals(other.engineGetSpec())); } public int hashCode() { return ecPublicKey.getQ().hashCode() ^ engineGetSpec().hashCode(); } private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { in.defaultReadObject(); byte[] enc = (byte[]) in.readObject(); populateFromPubKeyInfo(SubjectPublicKeyInfo.getInstance(ASN1Primitive.fromByteArray(enc))); } private void writeObject(ObjectOutputStream out) throws IOException { out.defaultWriteObject(); out.writeObject(this.getEncoded()); } ASN1Encodable getGostParams() { if (gostParams == null && ecSpec instanceof ECNamedCurveSpec) { this.gostParams = new GOST3410PublicKeyAlgParameters( ECGOST3410NamedCurves.getOID(((ECNamedCurveSpec) ecSpec).getName()), CryptoProObjectIdentifiers.gostR3411_94_CryptoProParamSet); } return gostParams; } }