Java tutorial
package org.bouncycastle.crypto.util; import java.io.IOException; import java.io.InputStream; import java.math.BigInteger; import org.bouncycastle.asn1.ASN1Encodable; import org.bouncycastle.asn1.ASN1InputStream; import org.bouncycastle.asn1.ASN1Integer; import org.bouncycastle.asn1.ASN1ObjectIdentifier; import org.bouncycastle.asn1.ASN1OctetString; import org.bouncycastle.asn1.ASN1Primitive; import org.bouncycastle.asn1.ASN1Sequence; import org.bouncycastle.asn1.cryptopro.CryptoProObjectIdentifiers; import org.bouncycastle.asn1.cryptopro.ECGOST3410NamedCurves; import org.bouncycastle.asn1.cryptopro.GOST3410PublicKeyAlgParameters; import org.bouncycastle.asn1.edec.EdECObjectIdentifiers; import org.bouncycastle.asn1.oiw.ElGamalParameter; import org.bouncycastle.asn1.oiw.OIWObjectIdentifiers; import org.bouncycastle.asn1.pkcs.DHParameter; import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers; import org.bouncycastle.asn1.pkcs.PrivateKeyInfo; import org.bouncycastle.asn1.pkcs.RSAPrivateKey; import org.bouncycastle.asn1.rosstandart.RosstandartObjectIdentifiers; import org.bouncycastle.asn1.sec.ECPrivateKey; import org.bouncycastle.asn1.x509.AlgorithmIdentifier; import org.bouncycastle.asn1.x509.DSAParameter; import org.bouncycastle.asn1.x509.X509ObjectIdentifiers; import org.bouncycastle.asn1.x9.ECNamedCurveTable; import org.bouncycastle.asn1.x9.X962Parameters; import org.bouncycastle.asn1.x9.X9ECParameters; import org.bouncycastle.asn1.x9.X9ObjectIdentifiers; import org.bouncycastle.crypto.ec.CustomNamedCurves; import org.bouncycastle.crypto.params.AsymmetricKeyParameter; import org.bouncycastle.crypto.params.DHParameters; import org.bouncycastle.crypto.params.DHPrivateKeyParameters; import org.bouncycastle.crypto.params.DSAParameters; import org.bouncycastle.crypto.params.DSAPrivateKeyParameters; import org.bouncycastle.crypto.params.ECDomainParameters; import org.bouncycastle.crypto.params.ECGOST3410Parameters; import org.bouncycastle.crypto.params.ECNamedDomainParameters; import org.bouncycastle.crypto.params.ECPrivateKeyParameters; import org.bouncycastle.crypto.params.Ed25519PrivateKeyParameters; import org.bouncycastle.crypto.params.Ed448PrivateKeyParameters; import org.bouncycastle.crypto.params.ElGamalParameters; import org.bouncycastle.crypto.params.ElGamalPrivateKeyParameters; import org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters; import org.bouncycastle.crypto.params.X25519PrivateKeyParameters; import org.bouncycastle.crypto.params.X448PrivateKeyParameters; import org.bouncycastle.util.Arrays; /** * Factory for creating private key objects from PKCS8 PrivateKeyInfo objects. */ public class PrivateKeyFactory { /** * Create a private key parameter from a PKCS8 PrivateKeyInfo encoding. * * @param privateKeyInfoData the PrivateKeyInfo encoding * @return a suitable private key parameter * @throws IOException on an error decoding the key */ public static AsymmetricKeyParameter createKey(byte[] privateKeyInfoData) throws IOException { return createKey(PrivateKeyInfo.getInstance(ASN1Primitive.fromByteArray(privateKeyInfoData))); } /** * Create a private key parameter from a PKCS8 PrivateKeyInfo encoding read from a * stream. * * @param inStr the stream to read the PrivateKeyInfo encoding from * @return a suitable private key parameter * @throws IOException on an error decoding the key */ public static AsymmetricKeyParameter createKey(InputStream inStr) throws IOException { return createKey(PrivateKeyInfo.getInstance(new ASN1InputStream(inStr).readObject())); } /** * Create a private key parameter from the passed in PKCS8 PrivateKeyInfo object. * * @param keyInfo the PrivateKeyInfo object containing the key material * @return a suitable private key parameter * @throws IOException on an error decoding the key */ public static AsymmetricKeyParameter createKey(PrivateKeyInfo keyInfo) throws IOException { AlgorithmIdentifier algId = keyInfo.getPrivateKeyAlgorithm(); ASN1ObjectIdentifier algOID = algId.getAlgorithm(); if (algOID.equals(PKCSObjectIdentifiers.rsaEncryption) || algOID.equals(PKCSObjectIdentifiers.id_RSASSA_PSS) || algOID.equals(X509ObjectIdentifiers.id_ea_rsa)) { RSAPrivateKey keyStructure = RSAPrivateKey.getInstance(keyInfo.parsePrivateKey()); return new RSAPrivateCrtKeyParameters(keyStructure.getModulus(), keyStructure.getPublicExponent(), keyStructure.getPrivateExponent(), keyStructure.getPrime1(), keyStructure.getPrime2(), keyStructure.getExponent1(), keyStructure.getExponent2(), keyStructure.getCoefficient()); } // TODO? // else if (algOID.equals(X9ObjectIdentifiers.dhpublicnumber)) else if (algOID.equals(PKCSObjectIdentifiers.dhKeyAgreement)) { DHParameter params = DHParameter.getInstance(algId.getParameters()); ASN1Integer derX = (ASN1Integer) keyInfo.parsePrivateKey(); BigInteger lVal = params.getL(); int l = lVal == null ? 0 : lVal.intValue(); DHParameters dhParams = new DHParameters(params.getP(), params.getG(), null, l); return new DHPrivateKeyParameters(derX.getValue(), dhParams); } else if (algOID.equals(OIWObjectIdentifiers.elGamalAlgorithm)) { ElGamalParameter params = ElGamalParameter.getInstance(algId.getParameters()); ASN1Integer derX = (ASN1Integer) keyInfo.parsePrivateKey(); return new ElGamalPrivateKeyParameters(derX.getValue(), new ElGamalParameters(params.getP(), params.getG())); } else if (algOID.equals(X9ObjectIdentifiers.id_dsa)) { ASN1Integer derX = (ASN1Integer) keyInfo.parsePrivateKey(); ASN1Encodable de = algId.getParameters(); DSAParameters parameters = null; if (de != null) { DSAParameter params = DSAParameter.getInstance(de.toASN1Primitive()); parameters = new DSAParameters(params.getP(), params.getQ(), params.getG()); } return new DSAPrivateKeyParameters(derX.getValue(), parameters); } else if (algOID.equals(X9ObjectIdentifiers.id_ecPublicKey)) { X962Parameters params = X962Parameters.getInstance(algId.getParameters()); X9ECParameters x9; ECDomainParameters dParams; if (params.isNamedCurve()) { ASN1ObjectIdentifier oid = (ASN1ObjectIdentifier) params.getParameters(); x9 = CustomNamedCurves.getByOID(oid); if (x9 == null) { x9 = ECNamedCurveTable.getByOID(oid); } dParams = new ECNamedDomainParameters(oid, x9.getCurve(), x9.getG(), x9.getN(), x9.getH(), x9.getSeed()); } else { x9 = X9ECParameters.getInstance(params.getParameters()); dParams = new ECDomainParameters(x9.getCurve(), x9.getG(), x9.getN(), x9.getH(), x9.getSeed()); } ECPrivateKey ec = ECPrivateKey.getInstance(keyInfo.parsePrivateKey()); BigInteger d = ec.getKey(); return new ECPrivateKeyParameters(d, dParams); } else if (algOID.equals(EdECObjectIdentifiers.id_X25519)) { return new X25519PrivateKeyParameters(getRawKey(keyInfo, X25519PrivateKeyParameters.KEY_SIZE), 0); } else if (algOID.equals(EdECObjectIdentifiers.id_X448)) { return new X448PrivateKeyParameters(getRawKey(keyInfo, X448PrivateKeyParameters.KEY_SIZE), 0); } else if (algOID.equals(EdECObjectIdentifiers.id_Ed25519)) { return new Ed25519PrivateKeyParameters(getRawKey(keyInfo, Ed25519PrivateKeyParameters.KEY_SIZE), 0); } else if (algOID.equals(EdECObjectIdentifiers.id_Ed448)) { return new Ed448PrivateKeyParameters(getRawKey(keyInfo, Ed448PrivateKeyParameters.KEY_SIZE), 0); } else if (algOID.equals(CryptoProObjectIdentifiers.gostR3410_2001) || algOID.equals(RosstandartObjectIdentifiers.id_tc26_gost_3410_12_512) || algOID.equals(RosstandartObjectIdentifiers.id_tc26_gost_3410_12_256)) { GOST3410PublicKeyAlgParameters gostParams = GOST3410PublicKeyAlgParameters .getInstance(keyInfo.getPrivateKeyAlgorithm().getParameters()); ECGOST3410Parameters ecSpec = null; BigInteger d = null; ASN1Primitive p = keyInfo.getPrivateKeyAlgorithm().getParameters().toASN1Primitive(); if (p instanceof ASN1Sequence && (ASN1Sequence.getInstance(p).size() == 2 || ASN1Sequence.getInstance(p).size() == 3)) { ECDomainParameters ecP = ECGOST3410NamedCurves.getByOID(gostParams.getPublicKeyParamSet()); ecSpec = new ECGOST3410Parameters( new ECNamedDomainParameters(gostParams.getPublicKeyParamSet(), ecP), gostParams.getPublicKeyParamSet(), gostParams.getDigestParamSet(), gostParams.getEncryptionParamSet()); ASN1Encodable privKey = keyInfo.parsePrivateKey(); if (privKey instanceof ASN1Integer) { d = ASN1Integer.getInstance(privKey).getPositiveValue(); } else { byte[] dVal = Arrays.reverse(ASN1OctetString.getInstance(privKey).getOctets()); d = new BigInteger(1, dVal); } } else { X962Parameters params = X962Parameters .getInstance(keyInfo.getPrivateKeyAlgorithm().getParameters()); if (params.isNamedCurve()) { ASN1ObjectIdentifier oid = ASN1ObjectIdentifier.getInstance(params.getParameters()); X9ECParameters ecP = ECNamedCurveTable.getByOID(oid); if (ecP == null) { ECDomainParameters gParam = ECGOST3410NamedCurves.getByOID(oid); ecSpec = new ECGOST3410Parameters( new ECNamedDomainParameters(oid, gParam.getCurve(), gParam.getG(), gParam.getN(), gParam.getH(), gParam.getSeed()), gostParams.getPublicKeyParamSet(), gostParams.getDigestParamSet(), gostParams.getEncryptionParamSet()); } else { ecSpec = new ECGOST3410Parameters( new ECNamedDomainParameters(oid, ecP.getCurve(), ecP.getG(), ecP.getN(), ecP.getH(), ecP.getSeed()), gostParams.getPublicKeyParamSet(), gostParams.getDigestParamSet(), gostParams.getEncryptionParamSet()); } } else if (params.isImplicitlyCA()) { ecSpec = null; } else { X9ECParameters ecP = X9ECParameters.getInstance(params.getParameters()); ecSpec = new ECGOST3410Parameters( new ECNamedDomainParameters(algOID, ecP.getCurve(), ecP.getG(), ecP.getN(), ecP.getH(), ecP.getSeed()), gostParams.getPublicKeyParamSet(), gostParams.getDigestParamSet(), gostParams.getEncryptionParamSet()); } ASN1Encodable privKey = keyInfo.parsePrivateKey(); if (privKey instanceof ASN1Integer) { ASN1Integer derD = ASN1Integer.getInstance(privKey); d = derD.getValue(); } else { org.bouncycastle.asn1.sec.ECPrivateKey ec = org.bouncycastle.asn1.sec.ECPrivateKey .getInstance(privKey); d = ec.getKey(); } } return new ECPrivateKeyParameters(d, new ECGOST3410Parameters(ecSpec, gostParams.getPublicKeyParamSet(), gostParams.getDigestParamSet(), gostParams.getEncryptionParamSet())); } else { throw new RuntimeException("algorithm identifier in private key not recognised"); } } private static byte[] getRawKey(PrivateKeyInfo keyInfo, int expectedSize) throws IOException { byte[] result = ASN1OctetString.getInstance(keyInfo.parsePrivateKey()).getOctets(); if (expectedSize != result.length) { throw new RuntimeException("private key encoding has incorrect length"); } return result; } }