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 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
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/*
 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * $Id: DOMHMACSignatureMethod.java 1333415 2012-05-03 12:03:51Z coheigea $
 */
package org.jcp.xml.dsig.internal.dom;

import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.spec.HMACParameterSpec;
import javax.xml.crypto.dsig.spec.SignatureMethodParameterSpec;

import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SignatureException;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import org.jcp.xml.dsig.internal.MacOutputStream;

/**
 * DOM-based implementation of HMAC SignatureMethod.
 *
 * @author Sean Mullan
 */
public abstract class DOMHMACSignatureMethod extends AbstractDOMSignatureMethod {

    private static java.util.logging.Logger log =
        java.util.logging.Logger.getLogger("org.jcp.xml.dsig.internal.dom");

    // see RFC 4051 for these algorithm definitions
    static final String HMAC_SHA256 =
        "http://www.w3.org/2001/04/xmldsig-more#hmac-sha256";
    static final String HMAC_SHA384 =
        "http://www.w3.org/2001/04/xmldsig-more#hmac-sha384";
    static final String HMAC_SHA512 =
        "http://www.w3.org/2001/04/xmldsig-more#hmac-sha512";

    private Mac hmac;
    private int outputLength;
    private boolean outputLengthSet;
    private SignatureMethodParameterSpec params;

    /**
     * Creates a <code>DOMHMACSignatureMethod</code> with the specified params
     *
     * @param params algorithm-specific parameters (may be <code>null</code>)
     * @throws InvalidAlgorithmParameterException if params are inappropriate
     */
    DOMHMACSignatureMethod(AlgorithmParameterSpec params)
        throws InvalidAlgorithmParameterException
    {
        checkParams((SignatureMethodParameterSpec)params);
        this.params = (SignatureMethodParameterSpec)params;
    }

    /**
     * Creates a <code>DOMHMACSignatureMethod</code> from an element.
     *
     * @param smElem a SignatureMethod element
     */
    DOMHMACSignatureMethod(Element smElem) throws MarshalException {
        Element paramsElem = DOMUtils.getFirstChildElement(smElem);
        if (paramsElem != null) {
            params = unmarshalParams(paramsElem);
        }
        try {
            checkParams(params);
        } catch (InvalidAlgorithmParameterException iape) {
            throw new MarshalException(iape);
        }
    }

    void checkParams(SignatureMethodParameterSpec params)
        throws InvalidAlgorithmParameterException
    {
        if (params != null) {
            if (!(params instanceof HMACParameterSpec)) {
                throw new InvalidAlgorithmParameterException
                    ("params must be of type HMACParameterSpec");
            }
            outputLength = ((HMACParameterSpec)params).getOutputLength();
            outputLengthSet = true;
            if (log.isLoggable(java.util.logging.Level.FINE)) {
                log.log(java.util.logging.Level.FINE, "Setting outputLength from HMACParameterSpec to: " + outputLength);
            }
        }
    }

    public final AlgorithmParameterSpec getParameterSpec() {
        return params;
    }

    SignatureMethodParameterSpec unmarshalParams(Element paramsElem)
        throws MarshalException
    {
        outputLength = Integer.valueOf(paramsElem.getFirstChild().getNodeValue()).intValue();
        outputLengthSet = true;
        if (log.isLoggable(java.util.logging.Level.FINE)) {
            log.log(java.util.logging.Level.FINE, "unmarshalled outputLength: " + outputLength);
        }
        return new HMACParameterSpec(outputLength);
    }

    void marshalParams(Element parent, String prefix)
        throws MarshalException
    {
        Document ownerDoc = DOMUtils.getOwnerDocument(parent);
        Element hmacElem = DOMUtils.createElement(ownerDoc, "HMACOutputLength",
                                                  XMLSignature.XMLNS, prefix);
        hmacElem.appendChild(ownerDoc.createTextNode
           (String.valueOf(outputLength)));

        parent.appendChild(hmacElem);
    }

    boolean verify(Key key, SignedInfo si, byte[] sig,
                   XMLValidateContext context)
        throws InvalidKeyException, SignatureException, XMLSignatureException
    {
        if (key == null || si == null || sig == null) {
            throw new NullPointerException();
        }
        if (!(key instanceof SecretKey)) {
            throw new InvalidKeyException("key must be SecretKey");
        }
        if (hmac == null) {
            try {
                hmac = Mac.getInstance(getJCAAlgorithm());
            } catch (NoSuchAlgorithmException nsae) {
                throw new XMLSignatureException(nsae);
            }
        }
        if (outputLengthSet && outputLength < getDigestLength()) {
            throw new XMLSignatureException
                ("HMACOutputLength must not be less than " + getDigestLength());
        }
        hmac.init((SecretKey)key);
        ((DOMSignedInfo)si).canonicalize(context, new MacOutputStream(hmac));
        byte[] result = hmac.doFinal();

        return MessageDigest.isEqual(sig, result);
    }

    byte[] sign(Key key, SignedInfo si, XMLSignContext context)
        throws InvalidKeyException, XMLSignatureException
    {
        if (key == null || si == null) {
            throw new NullPointerException();
        }
        if (!(key instanceof SecretKey)) {
            throw new InvalidKeyException("key must be SecretKey");
        }
        if (hmac == null) {
            try {
                hmac = Mac.getInstance(getJCAAlgorithm());
            } catch (NoSuchAlgorithmException nsae) {
                throw new XMLSignatureException(nsae);
            }
        }
        if (outputLengthSet && outputLength < getDigestLength()) {
            throw new XMLSignatureException
                ("HMACOutputLength must not be less than " + getDigestLength());
        }
        hmac.init((SecretKey)key);
        ((DOMSignedInfo)si).canonicalize(context, new MacOutputStream(hmac));
        return hmac.doFinal();
    }

    boolean paramsEqual(AlgorithmParameterSpec spec) {
        if (getParameterSpec() == spec) {
            return true;
        }
        if (!(spec instanceof HMACParameterSpec)) {
            return false;
        }
        HMACParameterSpec ospec = (HMACParameterSpec)spec;

        return (outputLength == ospec.getOutputLength());
    }

    Type getAlgorithmType() {
        return Type.HMAC;
    }

    /**
     * Returns the output length of the hash/digest.
     */
    abstract int getDigestLength();

    static final class SHA1 extends DOMHMACSignatureMethod {
        SHA1(AlgorithmParameterSpec params)
            throws InvalidAlgorithmParameterException {
            super(params);
        }
        SHA1(Element dmElem) throws MarshalException {
            super(dmElem);
        }
        public String getAlgorithm() {
            return SignatureMethod.HMAC_SHA1;
        }
        String getJCAAlgorithm() {
            return "HmacSHA1";
        }
        int getDigestLength() {
            return 160;
        }
    }

    static final class SHA256 extends DOMHMACSignatureMethod {
        SHA256(AlgorithmParameterSpec params)
            throws InvalidAlgorithmParameterException {
            super(params);
        }
        SHA256(Element dmElem) throws MarshalException {
            super(dmElem);
        }
        public String getAlgorithm() {
            return HMAC_SHA256;
        }
        String getJCAAlgorithm() {
            return "HmacSHA256";
        }
        int getDigestLength() {
            return 256;
        }
    }

    static final class SHA384 extends DOMHMACSignatureMethod {
        SHA384(AlgorithmParameterSpec params)
            throws InvalidAlgorithmParameterException {
            super(params);
        }
        SHA384(Element dmElem) throws MarshalException {
            super(dmElem);
        }
        public String getAlgorithm() {
            return HMAC_SHA384;
        }
        String getJCAAlgorithm() {
            return "HmacSHA384";
        }
        int getDigestLength() {
            return 384;
        }
    }

    static final class SHA512 extends DOMHMACSignatureMethod {
        SHA512(AlgorithmParameterSpec params)
            throws InvalidAlgorithmParameterException {
            super(params);
        }
        SHA512(Element dmElem) throws MarshalException {
            super(dmElem);
        }
        public String getAlgorithm() {
            return HMAC_SHA512;
        }
        String getJCAAlgorithm() {
            return "HmacSHA512";
        }
        int getDigestLength() {
            return 512;
        }
    }
}
