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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.

 */

package com.sun.org.apache.xml.internal.security.algorithms.implementations;

import java.io.IOException;

import java.security.InvalidAlgorithmParameterException;

import java.security.InvalidKeyException;

import java.security.Key;

import java.security.PrivateKey;

import java.security.PublicKey;

import java.security.SecureRandom;

import java.security.Signature;

import java.security.SignatureException;

import java.security.interfaces.DSAKey;

import java.security.spec.AlgorithmParameterSpec;

import com.sun.org.apache.xml.internal.security.algorithms.JCEMapper;

import com.sun.org.apache.xml.internal.security.algorithms.SignatureAlgorithmSpi;

import com.sun.org.apache.xml.internal.security.signature.XMLSignature;

import com.sun.org.apache.xml.internal.security.signature.XMLSignatureException;

import com.sun.org.apache.xml.internal.security.utils.Constants;

import com.sun.org.apache.xml.internal.security.utils.JavaUtils;

import com.sun.org.apache.xml.internal.security.utils.XMLUtils;

public class SignatureDSA extends SignatureAlgorithmSpi {

    public static final String URI = Constants.SignatureSpecNS + "dsa-sha1";

    private static final com.sun.org.slf4j.internal.Logger LOG =

        com.sun.org.slf4j.internal.LoggerFactory.getLogger(SignatureDSA.class);

    /** Field algorithm */

    private Signature signatureAlgorithm;

    /** size of Q */

    private int size;

    /**

     * Method engineGetURI

     *

     * {@inheritDoc}

     */

    protected String engineGetURI() {

        return XMLSignature.ALGO_ID_SIGNATURE_DSA;

    }

    /**

     * Constructor SignatureDSA

     *

     * @throws XMLSignatureException

     */

    public SignatureDSA() throws XMLSignatureException {

        String algorithmID = JCEMapper.translateURItoJCEID(engineGetURI());

        LOG.debug("Created SignatureDSA using {}", algorithmID);

        String provider = JCEMapper.getProviderId();

        try {

            if (provider == null) {

                this.signatureAlgorithm = Signature.getInstance(algorithmID);

            } else {

                this.signatureAlgorithm =

                    Signature.getInstance(algorithmID, provider);

            }

        } catch (java.security.NoSuchAlgorithmException ex) {

            Object[] exArgs = { algorithmID, ex.getLocalizedMessage() };

            throw new XMLSignatureException("algorithms.NoSuchAlgorithm", exArgs);

        } catch (java.security.NoSuchProviderException ex) {

            Object[] exArgs = { algorithmID, ex.getLocalizedMessage() };

            throw new XMLSignatureException("algorithms.NoSuchAlgorithm", exArgs);

        }

    }

    /**

     * {@inheritDoc}

     */

    protected void engineSetParameter(AlgorithmParameterSpec params)

        throws XMLSignatureException {

        try {

            this.signatureAlgorithm.setParameter(params);

        } catch (InvalidAlgorithmParameterException ex) {

            throw new XMLSignatureException(ex);

        }

    }

    /**

     * {@inheritDoc}

     */

    protected boolean engineVerify(byte[] signature)

        throws XMLSignatureException {

        try {

            if (LOG.isDebugEnabled()) {

                LOG.debug("Called DSA.verify() on " + XMLUtils.encodeToString(signature));

            }

            byte[] jcebytes = JavaUtils.convertDsaXMLDSIGtoASN1(signature,

                                                                size/8);

            return this.signatureAlgorithm.verify(jcebytes);

        } catch (SignatureException ex) {

            throw new XMLSignatureException(ex);

        } catch (IOException ex) {

            throw new XMLSignatureException(ex);

        }

    }

    /**

     * {@inheritDoc}

     */

    protected void engineInitVerify(Key publicKey) throws XMLSignatureException {

        if (!(publicKey instanceof PublicKey)) {

            String supplied = null;

            if (publicKey != null) {

                supplied = publicKey.getClass().getName();

            }

            String needed = PublicKey.class.getName();

            Object exArgs[] = { supplied, needed };

            throw new XMLSignatureException("algorithms.WrongKeyForThisOperation", exArgs);

        }

        try {

            this.signatureAlgorithm.initVerify((PublicKey) publicKey);

        } catch (InvalidKeyException ex) {

            // reinstantiate Signature object to work around bug in JDK

            // see: http://bugs.sun.com/view_bug.do?bug_id=4953555

            Signature sig = this.signatureAlgorithm;

            try {

                this.signatureAlgorithm = Signature.getInstance(signatureAlgorithm.getAlgorithm());

            } catch (Exception e) {

                // this shouldn't occur, but if it does, restore previous

                // Signature

                LOG.debug("Exception when reinstantiating Signature: {}", e);

                this.signatureAlgorithm = sig;

            }

            throw new XMLSignatureException(ex);

        }

        size = ((DSAKey)publicKey).getParams().getQ().bitLength();

    }

    /**

     * {@inheritDoc}

     */

    protected byte[] engineSign() throws XMLSignatureException {

        try {

            byte jcebytes[] = this.signatureAlgorithm.sign();

            return JavaUtils.convertDsaASN1toXMLDSIG(jcebytes, size/8);

        } catch (IOException ex) {

            throw new XMLSignatureException(ex);

        } catch (SignatureException ex) {

            throw new XMLSignatureException(ex);

        }

    }

    /**

     * {@inheritDoc}

     */

    protected void engineInitSign(Key privateKey, SecureRandom secureRandom)

        throws XMLSignatureException {

        if (!(privateKey instanceof PrivateKey)) {

            String supplied = null;

            if (privateKey != null) {

                supplied = privateKey.getClass().getName();

            }

            String needed = PrivateKey.class.getName();

            Object exArgs[] = { supplied, needed };

            throw new XMLSignatureException("algorithms.WrongKeyForThisOperation", exArgs);

        }

        try {

            if (secureRandom == null) {

                this.signatureAlgorithm.initSign((PrivateKey) privateKey);

            } else {

                this.signatureAlgorithm.initSign((PrivateKey) privateKey, secureRandom);

            }

        } catch (InvalidKeyException ex) {

            throw new XMLSignatureException(ex);

        }

        size = ((DSAKey)privateKey).getParams().getQ().bitLength();

    }

    /**

     * {@inheritDoc}

     */

    protected void engineInitSign(Key privateKey) throws XMLSignatureException {

        engineInitSign(privateKey, (SecureRandom)null);

    }

    /**

     * {@inheritDoc}

     */

    protected void engineUpdate(byte[] input) throws XMLSignatureException {

        try {

            this.signatureAlgorithm.update(input);

        } catch (SignatureException ex) {

            throw new XMLSignatureException(ex);

        }

    }

    /**

     * {@inheritDoc}

     */

    protected void engineUpdate(byte input) throws XMLSignatureException {

        try {

            this.signatureAlgorithm.update(input);

        } catch (SignatureException ex) {

            throw new XMLSignatureException(ex);

        }

    }

    /**

     * {@inheritDoc}

     */

    protected void engineUpdate(byte buf[], int offset, int len) throws XMLSignatureException {

        try {

            this.signatureAlgorithm.update(buf, offset, len);

        } catch (SignatureException ex) {

            throw new XMLSignatureException(ex);

        }

    }

    /**

     * Method engineGetJCEAlgorithmString

     *

     * {@inheritDoc}

     */

    protected String engineGetJCEAlgorithmString() {

        return this.signatureAlgorithm.getAlgorithm();

    }

    /**

     * Method engineGetJCEProviderName

     *

     * {@inheritDoc}

     */

    protected String engineGetJCEProviderName() {

        return this.signatureAlgorithm.getProvider().getName();

    }

    /**

     * Method engineSetHMACOutputLength

     *

     * @param HMACOutputLength

     * @throws XMLSignatureException

     */

    protected void engineSetHMACOutputLength(int HMACOutputLength) throws XMLSignatureException {

        throw new XMLSignatureException("algorithms.HMACOutputLengthOnlyForHMAC");

    }

    /**

     * Method engineInitSign

     *

     * @param signingKey

     * @param algorithmParameterSpec

     * @throws XMLSignatureException

     */

    protected void engineInitSign(

        Key signingKey, AlgorithmParameterSpec algorithmParameterSpec

    ) throws XMLSignatureException {

        throw new XMLSignatureException("algorithms.CannotUseAlgorithmParameterSpecOnDSA");

    }

    public static class SHA256 extends SignatureDSA {

        public SHA256() throws XMLSignatureException {

            super();

        }

        public String engineGetURI() {

            return XMLSignature.ALGO_ID_SIGNATURE_DSA_SHA256;

        }

    }

}