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The Apache PDFBox library is an open source Java tool for working with PDF documents.
/*
* 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 org.apache.pdfbox.cos.COSArray;
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.cos.COSString;
/**
* This class is a specialized view of the encryption dictionary of a PDF document.
* It contains a low level dictionary (COSDictionary) and provides the methods to
* manage its fields.
*
* The available fields are the ones who are involved by standard security handler
* and public key security handler.
*
* @author Ben Litchfield
* @author Benoit Guillon
*/
public class PDEncryption
{
/**
* See PDF Reference 1.4 Table 3.13.
*/
public static final int VERSION0_UNDOCUMENTED_UNSUPPORTED = 0;
/**
* See PDF Reference 1.4 Table 3.13.
*/
public static final int VERSION1_40_BIT_ALGORITHM = 1;
/**
* See PDF Reference 1.4 Table 3.13.
*/
public static final int VERSION2_VARIABLE_LENGTH_ALGORITHM = 2;
/**
* See PDF Reference 1.4 Table 3.13.
*/
public static final int VERSION3_UNPUBLISHED_ALGORITHM = 3;
/**
* See PDF Reference 1.4 Table 3.13.
*/
public static final int VERSION4_SECURITY_HANDLER = 4;
/**
* The default security handler.
*/
public static final String DEFAULT_NAME = "Standard";
/**
* The default length for the encryption key.
*/
public static final int DEFAULT_LENGTH = 40;
/**
* The default version, according to the PDF Reference.
*/
public static final int DEFAULT_VERSION = VERSION0_UNDOCUMENTED_UNSUPPORTED;
private final COSDictionary dictionary;
private SecurityHandler securityHandler;
/**
* creates a new empty encryption dictionary.
*/
public PDEncryption()
{
dictionary = new COSDictionary();
}
/**
* creates a new encryption dictionary from the low level dictionary provided.
* @param dictionary a COS encryption dictionary
*/
public PDEncryption(COSDictionary dictionary)
{
this.dictionary = dictionary;
securityHandler = SecurityHandlerFactory.INSTANCE.newSecurityHandlerForFilter(getFilter());
}
/**
* Returns the security handler specified in the dictionary's Filter entry.
* @return a security handler instance
* @throws IOException if there is no security handler available which matches the Filter
*/
public SecurityHandler getSecurityHandler() throws IOException
{
if (securityHandler == null)
{
throw new IOException("No security handler for filter " + getFilter());
}
return securityHandler;
}
/**
* Sets the security handler used in this encryption dictionary
* @param securityHandler new security handler
*/
public void setSecurityHandler(SecurityHandler securityHandler)
{
this.securityHandler = securityHandler;
// TODO set Filter (currently this is done by the security handlers)
}
/**
* Returns true if the security handler specified in the dictionary's Filter is available.
* @return true if the security handler is available
*/
public boolean hasSecurityHandler()
{
return securityHandler == null;
}
/**
* This will get the dictionary associated with this encryption dictionary.
*
* @return The COS dictionary that this object wraps.
*/
public COSDictionary getCOSDictionary()
{
return dictionary;
}
/**
* Sets the filter entry of the encryption dictionary.
*
* @param filter The filter name.
*/
public void setFilter(String filter)
{
dictionary.setItem(COSName.FILTER, COSName.getPDFName(filter));
}
/**
* Get the name of the filter.
*
* @return The filter name contained in this encryption dictionary.
*/
public final String getFilter()
{
return dictionary.getNameAsString( COSName.FILTER );
}
/**
* Get the name of the subfilter.
*
* @return The subfilter name contained in this encryption dictionary.
*/
public String getSubFilter()
{
return dictionary.getNameAsString( COSName.SUB_FILTER );
}
/**
* Set the subfilter entry of the encryption dictionary.
*
* @param subfilter The value of the subfilter field.
*/
public void setSubFilter(String subfilter)
{
dictionary.setName(COSName.SUB_FILTER, subfilter);
}
/**
* This will set the V entry of the encryption dictionary.
* See PDF Reference 1.4 Table 3.13.
* Note: This value is used to decrypt the pdf document. If you change this when
* the document is encrypted then decryption will fail!.
*
* @param version The new encryption version.
*/
public void setVersion(int version)
{
dictionary.setInt(COSName.V, version);
}
/**
* This will return the V entry of the encryption dictionary.
* See PDF Reference 1.4 Table 3.13.
*
* @return The encryption version to use.
*/
public int getVersion()
{
return dictionary.getInt( COSName.V, 0 );
}
/**
* This will set the number of bits to use for the encryption algorithm.
*
* @param length The new key length.
*/
public void setLength(int length)
{
dictionary.setInt(COSName.LENGTH, length);
}
/**
* This will return the Length entry of the encryption dictionary.
* The length in bits for the encryption algorithm. This will return a multiple of 8.
*
* @return The length in bits for the encryption algorithm
*/
public int getLength()
{
return dictionary.getInt( COSName.LENGTH, 40 );
}
/**
* This will set the R entry of the encryption dictionary.
*
* See PDF Reference 1.4 Table 3.14.
*
*
* Note: This value is used to decrypt the pdf document. If you change this when the document is encrypted then
* decryption will fail!.
*
* @param revision The new encryption version.
*/
public void setRevision(int revision)
{
dictionary.setInt(COSName.R, revision);
}
/**
* This will return the R entry of the encryption dictionary.
* See PDF Reference 1.4 Table 3.14.
*
* @return The encryption revision to use.
*/
public int getRevision()
{
return dictionary.getInt( COSName.R, DEFAULT_VERSION );
}
/**
* This will set the O entry in the standard encryption dictionary.
*
* @param o A 32 byte array or null if there is no owner key.
*
* @throws IOException If there is an error setting the data.
*/
public void setOwnerKey(byte[] o) throws IOException
{
dictionary.setItem(COSName.O, new COSString(o));
}
/**
* This will get the O entry in the standard encryption dictionary.
*
* @return A 32 byte array or null if there is no owner key.
*
* @throws IOException If there is an error accessing the data.
*/
public byte[] getOwnerKey() throws IOException
{
byte[] o = null;
COSString owner = (COSString) dictionary.getDictionaryObject( COSName.O );
if( owner != null )
{
o = owner.getBytes();
}
return o;
}
/**
* This will set the U entry in the standard encryption dictionary.
*
* @param u A 32 byte array.
*
* @throws IOException If there is an error setting the data.
*/
public void setUserKey(byte[] u) throws IOException
{
dictionary.setItem(COSName.U, new COSString(u));
}
/**
* This will get the U entry in the standard encryption dictionary.
*
* @return A 32 byte array or null if there is no user key.
*
* @throws IOException If there is an error accessing the data.
*/
public byte[] getUserKey() throws IOException
{
byte[] u = null;
COSString user = (COSString) dictionary.getDictionaryObject( COSName.U );
if( user != null )
{
u = user.getBytes();
}
return u;
}
/**
* This will set the OE entry in the standard encryption dictionary.
*
* @param oe A 32 byte array or null if there is no owner encryption key.
*
* @throws IOException If there is an error setting the data.
*/
public void setOwnerEncryptionKey(byte[] oe) throws IOException
{
dictionary.setItem( COSName.OE, new COSString(oe) );
}
/**
* This will get the OE entry in the standard encryption dictionary.
*
* @return A 32 byte array or null if there is no owner encryption key.
*
* @throws IOException If there is an error accessing the data.
*/
public byte[] getOwnerEncryptionKey() throws IOException
{
byte[] oe = null;
COSString ownerEncryptionKey = (COSString)dictionary.getDictionaryObject( COSName.OE );
if( ownerEncryptionKey != null )
{
oe = ownerEncryptionKey.getBytes();
}
return oe;
}
/**
* This will set the UE entry in the standard encryption dictionary.
*
* @param ue A 32 byte array or null if there is no user encryption key.
*
* @throws IOException If there is an error setting the data.
*/
public void setUserEncryptionKey(byte[] ue) throws IOException
{
dictionary.setItem( COSName.UE, new COSString(ue) );
}
/**
* This will get the UE entry in the standard encryption dictionary.
*
* @return A 32 byte array or null if there is no user encryption key.
*
* @throws IOException If there is an error accessing the data.
*/
public byte[] getUserEncryptionKey() throws IOException
{
byte[] ue = null;
COSString userEncryptionKey = (COSString)dictionary.getDictionaryObject( COSName.UE );
if( userEncryptionKey != null )
{
ue = userEncryptionKey.getBytes();
}
return ue;
}
/**
* This will set the permissions bit mask.
*
* @param permissions The new permissions bit mask
*/
public void setPermissions(int permissions)
{
dictionary.setInt(COSName.P, permissions);
}
/**
* This will get the permissions bit mask.
*
* @return The permissions bit mask.
*/
public int getPermissions()
{
return dictionary.getInt( COSName.P, 0 );
}
/**
* Will get the EncryptMetaData dictionary info.
*
* @return true if EncryptMetaData is explicitly set to false (the default is true)
*/
public boolean isEncryptMetaData()
{
// default is true (see 7.6.3.2 Standard Encryption Dictionary PDF 32000-1:2008)
boolean encryptMetaData = true;
COSBase value = dictionary.getDictionaryObject(COSName.ENCRYPT_META_DATA);
if (value instanceof COSBoolean)
{
encryptMetaData = ((COSBoolean)value).getValue();
}
return encryptMetaData;
}
/**
* This will set the Recipients field of the dictionary. This field contains an array
* of string.
* @param recipients the array of bytes arrays to put in the Recipients field.
* @throws IOException If there is an error setting the data.
*/
public void setRecipients(byte[][] recipients) throws IOException
{
COSArray array = new COSArray();
for (byte[] recipient : recipients)
{
COSString recip = new COSString(recipient);
array.add(recip);
}
dictionary.setItem(COSName.RECIPIENTS, array);
}
/**
* Returns the number of recipients contained in the Recipients field of the dictionary.
*
* @return the number of recipients contained in the Recipients field.
*/
public int getRecipientsLength()
{
COSArray array = (COSArray) dictionary.getItem(COSName.RECIPIENTS);
return array.size();
}
/**
* returns the COSString contained in the Recipients field at position i.
*
* @param i the position in the Recipients field array.
*
* @return a COSString object containing information about the recipient number i.
*/
public COSString getRecipientStringAt(int i)
{
COSArray array = (COSArray) dictionary.getItem(COSName.RECIPIENTS);
return (COSString)array.get(i);
}
/**
* Returns the standard crypt filter.
*
* @return the standard crypt filter if available.
*/
public PDCryptFilterDictionary getStdCryptFilterDictionary()
{
return getCryptFilterDictionary(COSName.STD_CF);
}
/**
* Returns the crypt filter with the given name.
*
* @param cryptFilterName the name of the crypt filter
*
* @return the crypt filter with the given name if available
*/
public PDCryptFilterDictionary getCryptFilterDictionary(COSName cryptFilterName)
{
COSDictionary cryptFilterDictionary = (COSDictionary) dictionary.getDictionaryObject( COSName.CF );
if (cryptFilterDictionary != null)
{
COSDictionary stdCryptFilterDictionary = (COSDictionary)cryptFilterDictionary.getDictionaryObject(cryptFilterName);
if (stdCryptFilterDictionary != null)
{
return new PDCryptFilterDictionary(stdCryptFilterDictionary);
}
}
return null;
}
/**
* Sets the crypt filter with the given name.
*
* @param cryptFilterName the name of the crypt filter
* @param cryptFilterDictionary the crypt filter to set
*/
public void setCryptFilterDictionary(COSName cryptFilterName, PDCryptFilterDictionary cryptFilterDictionary)
{
COSDictionary cfDictionary = (COSDictionary)dictionary.getDictionaryObject( COSName.CF );
if (cfDictionary == null)
{
cfDictionary = new COSDictionary();
dictionary.setItem(COSName.CF, cfDictionary);
}
cfDictionary.setItem(cryptFilterName, cryptFilterDictionary.getCOSDictionary());
}
/**
* Sets the standard crypt filter.
*
* @param cryptFilterDictionary the standard crypt filter to set
*/
public void setStdCryptFilterDictionary(PDCryptFilterDictionary cryptFilterDictionary)
{
setCryptFilterDictionary(COSName.STD_CF, cryptFilterDictionary);
}
/**
* Returns the name of the filter which is used for de/encrypting streams.
* Default value is "Identity".
*
* @return the name of the filter
*/
public COSName getStreamFilterName()
{
COSName stmF = (COSName) dictionary.getDictionaryObject( COSName.STM_F );
if (stmF == null)
{
stmF = COSName.IDENTITY;
}
return stmF;
}
/**
* Sets the name of the filter which is used for de/encrypting streams.
*
* @param streamFilterName the name of the filter
*/
public void setStreamFilterName(COSName streamFilterName)
{
dictionary.setItem(COSName.STM_F, streamFilterName);
}
/**
* Returns the name of the filter which is used for de/encrypting strings.
* Default value is "Identity".
*
* @return the name of the filter
*/
public COSName getStringFilterName()
{
COSName strF = (COSName) dictionary.getDictionaryObject( COSName.STR_F );
if (strF == null)
{
strF = COSName.IDENTITY;
}
return strF;
}
/**
* Sets the name of the filter which is used for de/encrypting strings.
*
* @param stringFilterName the name of the filter
*/
public void setStringFilterName(COSName stringFilterName)
{
dictionary.setItem(COSName.STR_F, stringFilterName);
}
/**
* Set the Perms entry in the encryption dictionary.
*
* @param perms A 16 byte array.
*
* @throws IOException If there is an error setting the data.
*/
public void setPerms(byte[] perms) throws IOException
{
dictionary.setItem( COSName.PERMS, new COSString(perms) );
}
/**
* Get the Perms entry in the encryption dictionary.
*
* @return A 16 byte array or null if there is no Perms entry.
*
* @throws IOException If there is an error accessing the data.
*/
public byte[] getPerms() throws IOException
{
byte[] perms = null;
COSString permsCosString = (COSString)dictionary.getDictionaryObject( COSName.PERMS );
if( permsCosString != null )
{
perms = permsCosString.getBytes();
}
return perms;
}
/**
* remove CF, StmF, and StrF entries. This is to be called if V is not 4 or 5.
*/
public void removeV45filters()
{
dictionary.setItem(COSName.CF, null);
dictionary.setItem(COSName.STM_F, null);
dictionary.setItem(COSName.STR_F, null);
}
}