/*
 * 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.
/**
 * 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.
 */
/*
 * Copyright (c) 2005, 2009, 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/**
 * 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 DOMHMACSignatureMethod with the specified params
Params:
params – algorithm-specific parameters (may be null)
Throws:
InvalidAlgorithmParameterException – if params are inappropriate/**
     * 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 DOMHMACSignatureMethod from an element.
Params:
smElem – a SignatureMethod element/**
     * 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.
/**
     * 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;
        }
    }
}