# PDCryptFilterDictionary.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 org.apache.pdfbox.cos.COSBase;
    import org.apache.pdfbox.cos.COSBoolean;
    import org.apache.pdfbox.cos.COSDictionary;
    import org.apache.pdfbox.cos.COSName;
    import org.apache.pdfbox.pdmodel.common.COSObjectable;

    /**
     * This class is a specialized view of the crypt filter dictionary of a PDF document.
     * It contains a low level dictionary (COSDictionary) and provides the methods to
     * manage its fields.
     *
     */
    public class PDCryptFilterDictionary implements COSObjectable
    {

        /**
         * COS crypt filter dictionary.
         */
        protected COSDictionary cryptFilterDictionary = null;

        /**
         * creates a new empty crypt filter dictionary.
         */
        public PDCryptFilterDictionary()
        {
            cryptFilterDictionary = new COSDictionary();
        }

        /**
         * creates a new crypt filter dictionary from the low level dictionary provided.
         * @param d the low level dictionary that will be managed by the newly created object
         */
        public PDCryptFilterDictionary(COSDictionary d)
        {
            cryptFilterDictionary = d;
        }

        /**
         * This will get the dictionary associated with this crypt filter dictionary.
         *
         * @return The COS dictionary that this object wraps.
         */
        @Override
        public COSDictionary getCOSObject()
        {
            return cryptFilterDictionary;
        }

        /**
         * This will set the number of bits to use for the crypt filter algorithm.
         *
         * @param length The new key length.
         */
        public void setLength(int length)
        {
            cryptFilterDictionary.setInt(COSName.LENGTH, length);
        }

        /**
         * This will return the Length entry of the crypt filter dictionary.<br><br>
         * The length in <b>bits</b> for the crypt filter algorithm. This will return a multiple of 8.
         *
         * @return The length in bits for the encryption algorithm
         */
        public int getLength()
        {
            return cryptFilterDictionary.getInt( COSName.LENGTH, 40 );
        }

         /**
         * This will set the crypt filter method.
         * Allowed values are: NONE, V2, AESV2, AESV3
         *
         * @param cfm name of the crypt filter method.
         *
         */
        public void setCryptFilterMethod(COSName cfm)
        {
            cryptFilterDictionary.setItem( COSName.CFM, cfm );
        }

        /**
         * This will return the crypt filter method.
         * Allowed values are: NONE, V2, AESV2, AESV3
         *
         * @return the name of the crypt filter method.
         */
        public COSName getCryptFilterMethod()
        {
            return cryptFilterDictionary.getCOSName(COSName.CFM);
        }

        /**
         * Will get the EncryptMetaData dictionary info.
         *
         * @return true if EncryptMetaData is explicitly set (the default is true)
         */
        public boolean isEncryptMetaData()
        {
            COSBase value = getCOSObject().getDictionaryObject(COSName.ENCRYPT_META_DATA);
            if (value instanceof COSBoolean)
            {
                return ((COSBoolean) value).getValue();
            }

            // default is true (see 7.6.3.2 Standard Encryption Dictionary PDF 32000-1:2008)
            return true;
        }

        /**
         * Set the EncryptMetaData dictionary info.
         *
         * @param encryptMetaData true if EncryptMetaData shall be set.
         */
        public void setEncryptMetaData(boolean encryptMetaData)
        {
            getCOSObject().setBoolean(COSName.ENCRYPT_META_DATA, encryptMetaData);
        }
    }