# MessageDigests.java

    /*
     * 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 org.apache.pdfbox.pdmodel.encryption;

    import java.security.MessageDigest;
    import java.security.NoSuchAlgorithmException;

    /**
     * Utility class for creating MessageDigest instances.
     * @author John Hewson
     */
    final class MessageDigests
    {
        private MessageDigests()
        {
        }

        /**
         * @return MD5 message digest
         */
        static MessageDigest getMD5()
        {
            try
            {
                return MessageDigest.getInstance("MD5");
            }
            catch (NoSuchAlgorithmException e)
            {
                // should never happen
                throw new RuntimeException(e);
            }
        }

        /**
         * @return SHA-1 message digest
         */
        static MessageDigest getSHA1()
        {
            try
            {
                return MessageDigest.getInstance("SHA-1");
            }
            catch (NoSuchAlgorithmException e)
            {
                // should never happen
                throw new RuntimeException(e);
            }
        }

        /**
         * @return SHA-256 message digest
         */
        static MessageDigest getSHA256()
        {
            try
            {
                return MessageDigest.getInstance("SHA-256");
            }
            catch (NoSuchAlgorithmException e)
            {
                // should never happen
                throw new RuntimeException(e);
            }
        }
    }