# SecurityProvider.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.io.IOException;
    import java.lang.reflect.InvocationTargetException;
    import java.security.Provider;

    /**
     * Singleton which provides a security provider.
     *
     */
    public class SecurityProvider
    {
        private static Provider provider = null;

        private SecurityProvider()
        {
        }

        /**
         * Returns the provider to be used for advanced encrypting/decrypting. Default is the BouncyCastleProvider.
         *
         * @return the security provider
         *
         * @throws IOException if the default provider can't be instantiated
         */
        public static Provider getProvider() throws IOException
        {
            // TODO synchronize access
            if (provider == null)
            {
                try
                {
                    Class<Provider> providerClass = (Class<Provider>) Class
                            .forName("org.bouncycastle.jce.provider.BouncyCastleProvider");
                    provider = providerClass.getDeclaredConstructor().newInstance();
                }
                catch (ClassNotFoundException | InstantiationException | IllegalAccessException |
                       NoSuchMethodException | SecurityException | IllegalArgumentException |
                       InvocationTargetException ex)
                {
                    throw new IOException(ex);
                }
            }
            return provider;
        }

        /**
         * Set the provider to be used for advanced encrypting/decrypting.
         *
         * @param provider the security provider
         */
        public static void setProvider(Provider provider)
        {
            SecurityProvider.provider = provider;
        }
    }