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package org.pdfbox.pdmodel.encryption;
import java.io.IOException;
import org.pdfbox.cos.COSArray;
import org.pdfbox.cos.COSDictionary;
import org.pdfbox.cos.COSName;
import org.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 <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
* @author Benoit Guillon (benoit.guillon@snv.jussieu.fr)
*
* @version $Revision: 1.7 $
*/
public class PDEncryptionDictionary
{
/**
* 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;
/**
* COS encryption dictionary.
*/
protected COSDictionary encryptionDictionary = null;
/**
* creates a new empty encryption dictionary.
*/
public PDEncryptionDictionary()
{
encryptionDictionary = new COSDictionary();
}
/**
* creates a new encryption dictionary from the low level dictionary provided.
* @param d the low level dictionary that will be managed by the newly created object
*/
public PDEncryptionDictionary(COSDictionary d)
{
encryptionDictionary = d;
}
/**
* This will get the dictionary associated with this encryption dictionary.
*
* @return The COS dictionary that this object wraps.
*/
public COSDictionary getCOSDictionary()
{
return encryptionDictionary;
}
/**
* Sets the filter entry of the encryption dictionary.
*
* @param filter The filter name.
*/
public void setFilter(String filter)
{
encryptionDictionary.setItem( COSName.FILTER, COSName.getPDFName( filter ) );
}
/**
* Get the name of the filter.
*
* @return The filter name contained in this encryption dictionary.
*/
public String getFilter()
{
return encryptionDictionary.getNameAsString( COSName.FILTER );
}
/**
* Set the subfilter entry of the encryption dictionary.
*
* @param subfilter The value of the subfilter field.
*/
public void setSubFilter(String subfilter)
{
encryptionDictionary.setName( "SubFilter", subfilter );
}
/**
* This will set the V entry of the encryption dictionary.<br /><br />
* See PDF Reference 1.4 Table 3.13. <br /><br/>
* <b>Note: This value is used to decrypt the pdf document. If you change this when
* the document is encrypted then decryption will fail!.</b>
*
* @param version The new encryption version.
*/
public void setVersion(int version)
{
encryptionDictionary.setInt( "V", version );
}
/**
* This will return the V entry of the encryption dictionary.<br /><br />
* See PDF Reference 1.4 Table 3.13.
*
* @return The encryption version to use.
*/
public int getVersion()
{
return encryptionDictionary.getInt( "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)
{
encryptionDictionary.setInt("Length", length);
}
/**
* This will return the Length entry of the encryption dictionary.<br /><br />
* The length in <b>bits</b> for the encryption algorithm. This will return a multiple of 8.
*
* @return The length in bits for the encryption algorithm
*/
public int getLength()
{
return encryptionDictionary.getInt( "Length", 40 );
}
/**
* This will set the R entry of the encryption dictionary.<br /><br />
* See PDF Reference 1.4 Table 3.14. <br /><br/>
*
* <b>Note: This value is used to decrypt the pdf document. If you change this when
* the document is encrypted then decryption will fail!.</b>
*
* @param revision The new encryption version.
*/
public void setRevision(int revision)
{
encryptionDictionary.setInt( "R", revision );
}
/**
* This will return the R entry of the encryption dictionary.<br /><br />
* See PDF Reference 1.4 Table 3.14.
*
* @return The encryption revision to use.
*/
public int getRevision()
{
return encryptionDictionary.getInt( "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
{
COSString owner = new COSString();
owner.append( o );
encryptionDictionary.setItem( COSName.getPDFName( "O" ), owner );
}
/**
* 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)encryptionDictionary.getDictionaryObject( COSName.getPDFName( "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
{
COSString user = new COSString();
user.append( u );
encryptionDictionary.setItem( COSName.getPDFName( "U" ), user );
}
/**
* 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)encryptionDictionary.getDictionaryObject( COSName.getPDFName( "U" ) );
if( user != null )
{
u = user.getBytes();
}
return u;
}
/**
* This will set the permissions bit mask.
*
* @param permissions The new permissions bit mask
*/
public void setPermissions(int permissions)
{
encryptionDictionary.setInt( "P", permissions );
}
/**
* This will get the permissions bit mask.
*
* @return The permissions bit mask.
*/
public int getPermissions()
{
return encryptionDictionary.getInt( "P", 0 );
}
/**
* 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(int i=0; i<recipients.length; i++)
{
COSString recip = new COSString();
recip.append(recipients[i]);
recip.setForceLiteralForm(true);
array.add(recip);
}
encryptionDictionary.setItem(COSName.getPDFName("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)encryptionDictionary.getItem(COSName.getPDFName("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)encryptionDictionary.getItem(COSName.getPDFName("Recipients"));
return (COSString)array.get(i);
}
}