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 * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.security.pkcs11;

import java.io.*;
import java.lang.ref.*;
import java.math.BigInteger;
import java.util.*;

import java.security.*;
import java.security.interfaces.*;
import java.security.spec.*;

import javax.crypto.*;
import javax.crypto.interfaces.*;
import javax.crypto.spec.*;

import sun.security.rsa.RSAPublicKeyImpl;

import sun.security.internal.interfaces.TlsMasterSecret;

import sun.security.pkcs11.wrapper.*;
import static sun.security.pkcs11.wrapper.PKCS11Constants.*;

import sun.security.util.DerValue;
import sun.security.util.Length;
import sun.security.util.ECUtil;

Key implementation classes.
In PKCS#11, the components of private and secret keys may or may not
be accessible. If they are, we use the algorithm specific key classes
(e.g. DSAPrivateKey) for compatibility with existing applications.
If the components are not accessible, we use a generic class that
only implements PrivateKey (or SecretKey). Whether the components of a
key are extractable is automatically determined when the key object is
created.
Author:
 Andreas Sterbenz
Since:
  1.5/**
 * Key implementation classes.
 *
 * In PKCS#11, the components of private and secret keys may or may not
 * be accessible. If they are, we use the algorithm specific key classes
 * (e.g. DSAPrivateKey) for compatibility with existing applications.
 * If the components are not accessible, we use a generic class that
 * only implements PrivateKey (or SecretKey). Whether the components of a
 * key are extractable is automatically determined when the key object is
 * created.
 *
 * @author  Andreas Sterbenz
 * @since   1.5
 */
abstract class P11Key implements Key, Length {

    private final static String PUBLIC = "public";
    private final static String PRIVATE = "private";
    private final static String SECRET = "secret";

    // type of key, one of (PUBLIC, PRIVATE, SECRET)
    final String type;

    // token instance
    final Token token;

    // algorithm name, returned by getAlgorithm(), etc.
    final String algorithm;

    // key id
    final long keyID;

    // effective key length of the key, e.g. 56 for a DES key
    final int keyLength;

    // flags indicating whether the key is a token object, sensitive, extractable
    final boolean tokenObject, sensitive, extractable;

    // phantom reference notification clean up for session keys
    private final SessionKeyRef sessionKeyRef;

    P11Key(String type, Session session, long keyID, String algorithm,
            int keyLength, CK_ATTRIBUTE[] attributes) {
        this.type = type;
        this.token = session.token;
        this.keyID = keyID;
        this.algorithm = algorithm;
        this.keyLength = keyLength;
        boolean tokenObject = false;
        boolean sensitive = false;
        boolean extractable = true;
        int n = (attributes == null) ? 0 : attributes.length;
        for (int i = 0; i < n; i++) {
            CK_ATTRIBUTE attr = attributes[i];
            if (attr.type == CKA_TOKEN) {
                tokenObject = attr.getBoolean();
            } else if (attr.type == CKA_SENSITIVE) {
                sensitive = attr.getBoolean();
            } else if (attr.type == CKA_EXTRACTABLE) {
                extractable = attr.getBoolean();
            }
        }
        this.tokenObject = tokenObject;
        this.sensitive = sensitive;
        this.extractable = extractable;
        if (tokenObject == false) {
            sessionKeyRef = new SessionKeyRef(this, keyID, session);
        } else {
            sessionKeyRef = null;
        }
    }

    // see JCA spec
    public final String getAlgorithm() {
        token.ensureValid();
        return algorithm;
    }

    // see JCA spec
    public final byte[] getEncoded() {
        byte[] b = getEncodedInternal();
        return (b == null) ? null : b.clone();
    }

    abstract byte[] getEncodedInternal();

    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        // equals() should never throw exceptions
        if (token.isValid() == false) {
            return false;
        }
        if (obj instanceof Key == false) {
            return false;
        }
        String thisFormat = getFormat();
        if (thisFormat == null) {
            // no encoding, key only equal to itself
            // XXX getEncoded() for unextractable keys will change that
            return false;
        }
        Key other = (Key)obj;
        if (thisFormat.equals(other.getFormat()) == false) {
            return false;
        }
        byte[] thisEnc = this.getEncodedInternal();
        byte[] otherEnc;
        if (obj instanceof P11Key) {
            otherEnc = ((P11Key)other).getEncodedInternal();
        } else {
            otherEnc = other.getEncoded();
        }
        return MessageDigest.isEqual(thisEnc, otherEnc);
    }

    public int hashCode() {
        // hashCode() should never throw exceptions
        if (token.isValid() == false) {
            return 0;
        }
        byte[] b1 = getEncodedInternal();
        if (b1 == null) {
            return 0;
        }
        int r = b1.length;
        for (int i = 0; i < b1.length; i++) {
            r += (b1[i] & 0xff) * 37;
        }
        return r;
    }

    protected Object writeReplace() throws ObjectStreamException {
        KeyRep.Type type;
        String format = getFormat();
        if (isPrivate() && "PKCS#8".equals(format)) {
            type = KeyRep.Type.PRIVATE;
        } else if (isPublic() && "X.509".equals(format)) {
            type = KeyRep.Type.PUBLIC;
        } else if (isSecret() && "RAW".equals(format)) {
            type = KeyRep.Type.SECRET;
        } else {
            // XXX short term serialization for unextractable keys
            throw new NotSerializableException
                ("Cannot serialize sensitive and unextractable keys");
        }
        return new KeyRep(type, getAlgorithm(), format, getEncoded());
    }

    public String toString() {
        token.ensureValid();
        String s1 = token.provider.getName() + " " + algorithm + " " + type
                + " key, " + keyLength + " bits";
        s1 += " (id " + keyID + ", "
                + (tokenObject ? "token" : "session") + " object";
        if (isPublic()) {
            s1 += ")";
        } else {
            s1 += ", " + (sensitive ? "" : "not ") + "sensitive";
            s1 += ", " + (extractable ? "" : "un") + "extractable)";
        }
        return s1;
    }

    
Return bit length of the key.
/**
     * Return bit length of the key.
     */
    @Override
    public int length() {
        return keyLength;
    }

    boolean isPublic() {
        return type == PUBLIC;
    }

    boolean isPrivate() {
        return type == PRIVATE;
    }

    boolean isSecret() {
        return type == SECRET;
    }

    void fetchAttributes(CK_ATTRIBUTE[] attributes) {
        Session tempSession = null;
        try {
            tempSession = token.getOpSession();
            token.p11.C_GetAttributeValue(tempSession.id(), keyID, attributes);
        } catch (PKCS11Exception e) {
            throw new ProviderException(e);
        } finally {
            token.releaseSession(tempSession);
        }
    }

    private final static CK_ATTRIBUTE[] A0 = new CK_ATTRIBUTE[0];

    private static CK_ATTRIBUTE[] getAttributes(Session session, long keyID,
            CK_ATTRIBUTE[] knownAttributes, CK_ATTRIBUTE[] desiredAttributes) {
        if (knownAttributes == null) {
            knownAttributes = A0;
        }
        for (int i = 0; i < desiredAttributes.length; i++) {
            // For each desired attribute, check to see if we have the value
            // available already. If everything is here, we save a native call.
            CK_ATTRIBUTE attr = desiredAttributes[i];
            for (CK_ATTRIBUTE known : knownAttributes) {
                if ((attr.type == known.type) && (known.pValue != null)) {
                    attr.pValue = known.pValue;
                    break; // break inner for loop
                }
            }
            if (attr.pValue == null) {
                // nothing found, need to call C_GetAttributeValue()
                for (int j = 0; j < i; j++) {
                    // clear values copied from knownAttributes
                    desiredAttributes[j].pValue = null;
                }
                try {
                    session.token.p11.C_GetAttributeValue
                            (session.id(), keyID, desiredAttributes);
                } catch (PKCS11Exception e) {
                    throw new ProviderException(e);
                }
                break; // break loop, goto return
            }
        }
        return desiredAttributes;
    }

    static SecretKey secretKey(Session session, long keyID, String algorithm,
            int keyLength, CK_ATTRIBUTE[] attributes) {
        attributes = getAttributes(session, keyID, attributes, new CK_ATTRIBUTE[] {
            new CK_ATTRIBUTE(CKA_TOKEN),
            new CK_ATTRIBUTE(CKA_SENSITIVE),
            new CK_ATTRIBUTE(CKA_EXTRACTABLE),
        });
        return new P11SecretKey(session, keyID, algorithm, keyLength, attributes);
    }

    static SecretKey masterSecretKey(Session session, long keyID, String algorithm,
            int keyLength, CK_ATTRIBUTE[] attributes, int major, int minor) {
        attributes = getAttributes(session, keyID, attributes, new CK_ATTRIBUTE[] {
            new CK_ATTRIBUTE(CKA_TOKEN),
            new CK_ATTRIBUTE(CKA_SENSITIVE),
            new CK_ATTRIBUTE(CKA_EXTRACTABLE),
        });
        return new P11TlsMasterSecretKey
                (session, keyID, algorithm, keyLength, attributes, major, minor);
    }

    // we assume that all components of public keys are always accessible
    static PublicKey publicKey(Session session, long keyID, String algorithm,
            int keyLength, CK_ATTRIBUTE[] attributes) {
        switch (algorithm) {
            case "RSA":
                return new P11RSAPublicKey
                    (session, keyID, algorithm, keyLength, attributes);
            case "DSA":
                return new P11DSAPublicKey
                    (session, keyID, algorithm, keyLength, attributes);
            case "DH":
                return new P11DHPublicKey
                    (session, keyID, algorithm, keyLength, attributes);
            case "EC":
                return new P11ECPublicKey
                    (session, keyID, algorithm, keyLength, attributes);
            default:
                throw new ProviderException
                    ("Unknown public key algorithm " + algorithm);
        }
    }

    static PrivateKey privateKey(Session session, long keyID, String algorithm,
            int keyLength, CK_ATTRIBUTE[] attributes) {
        attributes = getAttributes(session, keyID, attributes, new CK_ATTRIBUTE[] {
            new CK_ATTRIBUTE(CKA_TOKEN),
            new CK_ATTRIBUTE(CKA_SENSITIVE),
            new CK_ATTRIBUTE(CKA_EXTRACTABLE),
        });
        if (attributes[1].getBoolean() || (attributes[2].getBoolean() == false)) {
            return new P11PrivateKey
                (session, keyID, algorithm, keyLength, attributes);
        } else {
            switch (algorithm) {
                case "RSA":
                    // XXX better test for RSA CRT keys (single getAttributes() call)
                    // we need to determine whether this is a CRT key
                    // see if we can obtain the public exponent
                    // this should also be readable for sensitive/extractable keys
                    CK_ATTRIBUTE[] attrs2 = new CK_ATTRIBUTE[] {
                        new CK_ATTRIBUTE(CKA_PUBLIC_EXPONENT),
                    };
                    boolean crtKey;
                    try {
                        session.token.p11.C_GetAttributeValue
                            (session.id(), keyID, attrs2);
                        crtKey = (attrs2[0].pValue instanceof byte[]);
                    } catch (PKCS11Exception e) {
                        // ignore, assume not available
                        crtKey = false;
                    }
                    if (crtKey) {
                        return new P11RSAPrivateKey
                                (session, keyID, algorithm, keyLength, attributes);
                    } else {
                        return new P11RSAPrivateNonCRTKey
                                (session, keyID, algorithm, keyLength, attributes);
                    }
                case "DSA":
                    return new P11DSAPrivateKey
                            (session, keyID, algorithm, keyLength, attributes);
                case "DH":
                    return new P11DHPrivateKey
                            (session, keyID, algorithm, keyLength, attributes);
                case "EC":
                    return new P11ECPrivateKey
                            (session, keyID, algorithm, keyLength, attributes);
                default:
                    throw new ProviderException
                            ("Unknown private key algorithm " + algorithm);
            }
        }
    }

    // class for sensitive and unextractable private keys
    private static final class P11PrivateKey extends P11Key
                                                implements PrivateKey {
        private static final long serialVersionUID = -2138581185214187615L;

        P11PrivateKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PRIVATE, session, keyID, algorithm, keyLength, attributes);
        }
        // XXX temporary encoding for serialization purposes
        public String getFormat() {
            token.ensureValid();
            return null;
        }
        byte[] getEncodedInternal() {
            token.ensureValid();
            return null;
        }
    }

    private static class P11SecretKey extends P11Key implements SecretKey {
        private static final long serialVersionUID = -7828241727014329084L;
        private volatile byte[] encoded;
        P11SecretKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(SECRET, session, keyID, algorithm, keyLength, attributes);
        }
        public String getFormat() {
            token.ensureValid();
            if (sensitive || (extractable == false)) {
                return null;
            } else {
                return "RAW";
            }
        }
        byte[] getEncodedInternal() {
            token.ensureValid();
            if (getFormat() == null) {
                return null;
            }
            byte[] b = encoded;
            if (b == null) {
                synchronized (this) {
                    b = encoded;
                    if (b == null) {
                        Session tempSession = null;
                        try {
                            tempSession = token.getOpSession();
                            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                                new CK_ATTRIBUTE(CKA_VALUE),
                            };
                            token.p11.C_GetAttributeValue
                                (tempSession.id(), keyID, attributes);
                            b = attributes[0].getByteArray();
                        } catch (PKCS11Exception e) {
                            throw new ProviderException(e);
                        } finally {
                            token.releaseSession(tempSession);
                        }
                        encoded = b;
                    }
                }
            }
            return b;
        }
    }

    private static class P11TlsMasterSecretKey extends P11SecretKey
            implements TlsMasterSecret {
        private static final long serialVersionUID = -1318560923770573441L;

        private final int majorVersion, minorVersion;
        P11TlsMasterSecretKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes, int major, int minor) {
            super(session, keyID, algorithm, keyLength, attributes);
            this.majorVersion = major;
            this.minorVersion = minor;
        }
        public int getMajorVersion() {
            return majorVersion;
        }

        public int getMinorVersion() {
            return minorVersion;
        }
    }

    // RSA CRT private key
    private static final class P11RSAPrivateKey extends P11Key
                implements RSAPrivateCrtKey {
        private static final long serialVersionUID = 9215872438913515220L;

        private BigInteger n, e, d, p, q, pe, qe, coeff;
        private byte[] encoded;
        P11RSAPrivateKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PRIVATE, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (n != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_MODULUS),
                new CK_ATTRIBUTE(CKA_PUBLIC_EXPONENT),
                new CK_ATTRIBUTE(CKA_PRIVATE_EXPONENT),
                new CK_ATTRIBUTE(CKA_PRIME_1),
                new CK_ATTRIBUTE(CKA_PRIME_2),
                new CK_ATTRIBUTE(CKA_EXPONENT_1),
                new CK_ATTRIBUTE(CKA_EXPONENT_2),
                new CK_ATTRIBUTE(CKA_COEFFICIENT),
            };
            fetchAttributes(attributes);
            n = attributes[0].getBigInteger();
            e = attributes[1].getBigInteger();
            d = attributes[2].getBigInteger();
            p = attributes[3].getBigInteger();
            q = attributes[4].getBigInteger();
            pe = attributes[5].getBigInteger();
            qe = attributes[6].getBigInteger();
            coeff = attributes[7].getBigInteger();
        }
        public String getFormat() {
            token.ensureValid();
            return "PKCS#8";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    // XXX make constructor in SunRsaSign provider public
                    // and call it directly
                    KeyFactory factory = KeyFactory.getInstance
                        ("RSA", P11Util.getSunRsaSignProvider());
                    Key newKey = factory.translateKey(this);
                    encoded = newKey.getEncoded();
                } catch (GeneralSecurityException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getModulus() {
            fetchValues();
            return n;
        }
        public BigInteger getPublicExponent() {
            fetchValues();
            return e;
        }
        public BigInteger getPrivateExponent() {
            fetchValues();
            return d;
        }
        public BigInteger getPrimeP() {
            fetchValues();
            return p;
        }
        public BigInteger getPrimeQ() {
            fetchValues();
            return q;
        }
        public BigInteger getPrimeExponentP() {
            fetchValues();
            return pe;
        }
        public BigInteger getPrimeExponentQ() {
            fetchValues();
            return qe;
        }
        public BigInteger getCrtCoefficient() {
            fetchValues();
            return coeff;
        }
    }

    // RSA non-CRT private key
    private static final class P11RSAPrivateNonCRTKey extends P11Key
                implements RSAPrivateKey {
        private static final long serialVersionUID = 1137764983777411481L;

        private BigInteger n, d;
        private byte[] encoded;
        P11RSAPrivateNonCRTKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PRIVATE, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (n != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_MODULUS),
                new CK_ATTRIBUTE(CKA_PRIVATE_EXPONENT),
            };
            fetchAttributes(attributes);
            n = attributes[0].getBigInteger();
            d = attributes[1].getBigInteger();
        }
        public String getFormat() {
            token.ensureValid();
            return "PKCS#8";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    // XXX make constructor in SunRsaSign provider public
                    // and call it directly
                    KeyFactory factory = KeyFactory.getInstance
                        ("RSA", P11Util.getSunRsaSignProvider());
                    Key newKey = factory.translateKey(this);
                    encoded = newKey.getEncoded();
                } catch (GeneralSecurityException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getModulus() {
            fetchValues();
            return n;
        }
        public BigInteger getPrivateExponent() {
            fetchValues();
            return d;
        }
    }

    private static final class P11RSAPublicKey extends P11Key
                                                implements RSAPublicKey {
        private static final long serialVersionUID = -826726289023854455L;

        private BigInteger n, e;
        private byte[] encoded;
        P11RSAPublicKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PUBLIC, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (n != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_MODULUS),
                new CK_ATTRIBUTE(CKA_PUBLIC_EXPONENT),
            };
            fetchAttributes(attributes);
            n = attributes[0].getBigInteger();
            e = attributes[1].getBigInteger();
        }
        public String getFormat() {
            token.ensureValid();
            return "X.509";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    encoded = new RSAPublicKeyImpl(n, e).getEncoded();
                } catch (InvalidKeyException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getModulus() {
            fetchValues();
            return n;
        }
        public BigInteger getPublicExponent() {
            fetchValues();
            return e;
        }
        public String toString() {
            fetchValues();
            return super.toString() +  "\n  modulus: " + n
                + "\n  public exponent: " + e;
        }
    }

    private static final class P11DSAPublicKey extends P11Key
                                                implements DSAPublicKey {
        private static final long serialVersionUID = 5989753793316396637L;

        private BigInteger y;
        private DSAParams params;
        private byte[] encoded;
        P11DSAPublicKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PUBLIC, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (y != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_VALUE),
                new CK_ATTRIBUTE(CKA_PRIME),
                new CK_ATTRIBUTE(CKA_SUBPRIME),
                new CK_ATTRIBUTE(CKA_BASE),
            };
            fetchAttributes(attributes);
            y = attributes[0].getBigInteger();
            params = new DSAParameterSpec(
                attributes[1].getBigInteger(),
                attributes[2].getBigInteger(),
                attributes[3].getBigInteger()
            );
        }
        public String getFormat() {
            token.ensureValid();
            return "X.509";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    Key key = new sun.security.provider.DSAPublicKey
                            (y, params.getP(), params.getQ(), params.getG());
                    encoded = key.getEncoded();
                } catch (InvalidKeyException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getY() {
            fetchValues();
            return y;
        }
        public DSAParams getParams() {
            fetchValues();
            return params;
        }
        public String toString() {
            fetchValues();
            return super.toString() +  "\n  y: " + y + "\n  p: " + params.getP()
                + "\n  q: " + params.getQ() + "\n  g: " + params.getG();
        }
    }

    private static final class P11DSAPrivateKey extends P11Key
                                                implements DSAPrivateKey {
        private static final long serialVersionUID = 3119629997181999389L;

        private BigInteger x;
        private DSAParams params;
        private byte[] encoded;
        P11DSAPrivateKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PRIVATE, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (x != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_VALUE),
                new CK_ATTRIBUTE(CKA_PRIME),
                new CK_ATTRIBUTE(CKA_SUBPRIME),
                new CK_ATTRIBUTE(CKA_BASE),
            };
            fetchAttributes(attributes);
            x = attributes[0].getBigInteger();
            params = new DSAParameterSpec(
                attributes[1].getBigInteger(),
                attributes[2].getBigInteger(),
                attributes[3].getBigInteger()
            );
        }
        public String getFormat() {
            token.ensureValid();
            return "PKCS#8";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    Key key = new sun.security.provider.DSAPrivateKey
                            (x, params.getP(), params.getQ(), params.getG());
                    encoded = key.getEncoded();
                } catch (InvalidKeyException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getX() {
            fetchValues();
            return x;
        }
        public DSAParams getParams() {
            fetchValues();
            return params;
        }
    }

    private static final class P11DHPrivateKey extends P11Key
                                                implements DHPrivateKey {
        private static final long serialVersionUID = -1698576167364928838L;

        private BigInteger x;
        private DHParameterSpec params;
        private byte[] encoded;
        P11DHPrivateKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PRIVATE, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (x != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_VALUE),
                new CK_ATTRIBUTE(CKA_PRIME),
                new CK_ATTRIBUTE(CKA_BASE),
            };
            fetchAttributes(attributes);
            x = attributes[0].getBigInteger();
            params = new DHParameterSpec(
                attributes[1].getBigInteger(),
                attributes[2].getBigInteger()
            );
        }
        public String getFormat() {
            token.ensureValid();
            return "PKCS#8";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    DHPrivateKeySpec spec = new DHPrivateKeySpec
                        (x, params.getP(), params.getG());
                    KeyFactory kf = KeyFactory.getInstance
                        ("DH", P11Util.getSunJceProvider());
                    Key key = kf.generatePrivate(spec);
                    encoded = key.getEncoded();
                } catch (GeneralSecurityException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getX() {
            fetchValues();
            return x;
        }
        public DHParameterSpec getParams() {
            fetchValues();
            return params;
        }
    }

    private static final class P11DHPublicKey extends P11Key
                                                implements DHPublicKey {
        static final long serialVersionUID = -598383872153843657L;

        private BigInteger y;
        private DHParameterSpec params;
        private byte[] encoded;
        P11DHPublicKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PUBLIC, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (y != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_VALUE),
                new CK_ATTRIBUTE(CKA_PRIME),
                new CK_ATTRIBUTE(CKA_BASE),
            };
            fetchAttributes(attributes);
            y = attributes[0].getBigInteger();
            params = new DHParameterSpec(
                attributes[1].getBigInteger(),
                attributes[2].getBigInteger()
            );
        }
        public String getFormat() {
            token.ensureValid();
            return "X.509";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    DHPublicKeySpec spec = new DHPublicKeySpec
                        (y, params.getP(), params.getG());
                    KeyFactory kf = KeyFactory.getInstance
                        ("DH", P11Util.getSunJceProvider());
                    Key key = kf.generatePublic(spec);
                    encoded = key.getEncoded();
                } catch (GeneralSecurityException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getY() {
            fetchValues();
            return y;
        }
        public DHParameterSpec getParams() {
            fetchValues();
            return params;
        }
        public String toString() {
            fetchValues();
            return super.toString() +  "\n  y: " + y + "\n  p: " + params.getP()
                + "\n  g: " + params.getG();
        }
    }

    private static final class P11ECPrivateKey extends P11Key
                                                implements ECPrivateKey {
        private static final long serialVersionUID = -7786054399510515515L;

        private BigInteger s;
        private ECParameterSpec params;
        private byte[] encoded;
        P11ECPrivateKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PRIVATE, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (s != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_VALUE),
                new CK_ATTRIBUTE(CKA_EC_PARAMS, params),
            };
            fetchAttributes(attributes);
            s = attributes[0].getBigInteger();
            try {
                params = P11ECKeyFactory.decodeParameters
                            (attributes[1].getByteArray());
            } catch (Exception e) {
                throw new RuntimeException("Could not parse key values", e);
            }
        }
        public String getFormat() {
            token.ensureValid();
            return "PKCS#8";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    Key key = ECUtil.generateECPrivateKey(s, params);
                    encoded = key.getEncoded();
                } catch (InvalidKeySpecException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public BigInteger getS() {
            fetchValues();
            return s;
        }
        public ECParameterSpec getParams() {
            fetchValues();
            return params;
        }
    }

    private static final class P11ECPublicKey extends P11Key
                                                implements ECPublicKey {
        private static final long serialVersionUID = -6371481375154806089L;

        private ECPoint w;
        private ECParameterSpec params;
        private byte[] encoded;
        P11ECPublicKey(Session session, long keyID, String algorithm,
                int keyLength, CK_ATTRIBUTE[] attributes) {
            super(PUBLIC, session, keyID, algorithm, keyLength, attributes);
        }
        private synchronized void fetchValues() {
            token.ensureValid();
            if (w != null) {
                return;
            }
            CK_ATTRIBUTE[] attributes = new CK_ATTRIBUTE[] {
                new CK_ATTRIBUTE(CKA_EC_POINT),
                new CK_ATTRIBUTE(CKA_EC_PARAMS),
            };
            fetchAttributes(attributes);

            try {
                params = P11ECKeyFactory.decodeParameters
                            (attributes[1].getByteArray());
                byte[] ecKey = attributes[0].getByteArray();

                // Check whether the X9.63 encoding of an EC point is wrapped
                // in an ASN.1 OCTET STRING
                if (!token.config.getUseEcX963Encoding()) {
                    DerValue wECPoint = new DerValue(ecKey);

                    if (wECPoint.getTag() != DerValue.tag_OctetString) {
                        throw new IOException("Could not DER decode EC point." +
                            " Unexpected tag: " + wECPoint.getTag());
                    }
                    w = P11ECKeyFactory.decodePoint
                        (wECPoint.getDataBytes(), params.getCurve());

                } else {
                    w = P11ECKeyFactory.decodePoint(ecKey, params.getCurve());
                }

            } catch (Exception e) {
                throw new RuntimeException("Could not parse key values", e);
            }
        }
        public String getFormat() {
            token.ensureValid();
            return "X.509";
        }
        synchronized byte[] getEncodedInternal() {
            token.ensureValid();
            if (encoded == null) {
                fetchValues();
                try {
                    return ECUtil.x509EncodeECPublicKey(w, params);
                } catch (InvalidKeySpecException e) {
                    throw new ProviderException(e);
                }
            }
            return encoded;
        }
        public ECPoint getW() {
            fetchValues();
            return w;
        }
        public ECParameterSpec getParams() {
            fetchValues();
            return params;
        }
        public String toString() {
            fetchValues();
            return super.toString()
                + "\n  public x coord: " + w.getAffineX()
                + "\n  public y coord: " + w.getAffineY()
                + "\n  parameters: " + params;
        }
    }
}

/*
 * NOTE: Must use PhantomReference here and not WeakReference
 * otherwise the key maybe cleared before other objects which
 * still use these keys during finalization such as SSLSocket.
 */
final class SessionKeyRef extends PhantomReference<P11Key>
    implements Comparable<SessionKeyRef> {
    private static ReferenceQueue<P11Key> refQueue =
        new ReferenceQueue<P11Key>();
    private static Set<SessionKeyRef> refList =
        Collections.synchronizedSortedSet(new TreeSet<SessionKeyRef>());

    static ReferenceQueue<P11Key> referenceQueue() {
        return refQueue;
    }

    private static void drainRefQueueBounded() {
        while (true) {
            SessionKeyRef next = (SessionKeyRef) refQueue.poll();
            if (next == null) break;
            next.dispose();
        }
    }

    // handle to the native key
    private long keyID;
    private Session session;

    SessionKeyRef(P11Key key , long keyID, Session session) {
        super(key, refQueue);
        this.keyID = keyID;
        this.session = session;
        this.session.addObject();
        refList.add(this);
        // TBD: run at some interval and not every time?
        drainRefQueueBounded();
    }

    private void dispose() {
        refList.remove(this);
        if (session.token.isValid()) {
            Session newSession = null;
            try {
                newSession = session.token.getOpSession();
                session.token.p11.C_DestroyObject(newSession.id(), keyID);
            } catch (PKCS11Exception e) {
                // ignore
            } finally {
                this.clear();
                session.token.releaseSession(newSession);
                session.removeObject();
            }
        }
    }

    public int compareTo(SessionKeyRef other) {
        if (this.keyID == other.keyID) {
            return 0;
        } else {
            return (this.keyID < other.keyID) ? -1 : 1;
        }
    }
}