/*
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.
 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.
 */

package sun.security.krb5.internal.crypto;

import sun.security.krb5.Checksum;
import sun.security.krb5.KrbCryptoException;
import sun.security.krb5.internal.*;
import java.security.MessageDigest;

public final class RsaMd5CksumType extends CksumType {

    public RsaMd5CksumType() {
    }

    public int confounderSize() {
        return 0;
    }

    public int cksumType() {
        return Checksum.CKSUMTYPE_RSA_MD5;
    }

    public boolean isKeyed() {
        return false;
    }

    public int cksumSize() {
        return 16;
    }

    public int keyType() {
        return Krb5.KEYTYPE_NULL;
    }

    public int keySize() {
        return 0;
    }

    /**
     * Calculates checksum using MD5.
     * @param data the data used to generate the checksum.
     * @param size length of the data.
     * @return the checksum.
     *
     * @modified by Yanni Zhang, 12/08/99.
     */

    public byte[] calculateChecksum(byte[] data, int size,
            byte[] key, int usage) throws KrbCryptoException{
        MessageDigest md5;
        byte[] result = null;
        try {
            md5 = MessageDigest.getInstance("MD5");
        } catch (Exception e) {
            throw new KrbCryptoException("JCE provider may not be installed. " + e.getMessage());
        }
        try {
            md5.update(data);
            result = md5.digest();
        } catch (Exception e) {
            throw new KrbCryptoException(e.getMessage());
        }
        return result;
    }

    @Override
    public boolean verifyChecksum(byte[] data, int size,
            byte[] key, byte[] checksum, int usage)
            throws KrbCryptoException {
        try {
            byte[] calculated = MessageDigest.getInstance("MD5").digest(data);
            return CksumType.isChecksumEqual(calculated, checksum);
        } catch (Exception e) {
            return false;
        }
    }
}
