Package org.faceless.pdf2

Class StandardEncryptionHandler

  • All Implemented Interfaces:
    Cloneable
    Direct Known Subclasses:
    PasswordPromptEncryptionHandler
    public class StandardEncryptionHandler
extends EncryptionHandler

    Represents the standard Acrobat encryption algorithm, both 40-bit and 128-bit variants. The only methods the end-user need worry about are setUserPassword(java.lang.String), setOwnerPassword(java.lang.String), and choosing an appropriate encryption level by calling one of

    Unless you are generating a PDF for a specific workflow that requires an older encryption standard we strongly 256-bit AES, which was first specified in 2011 and is very widely supported. But note that the AES/GCM-256 mode was first specified in 2023, added to this API around April 2024: this encryption mode was not supported by any other product at that point.

    A typical use would be to create a PDF document that cannot be printed. This is done like so: 

      StandardEncryptionHandler encrypt = new StandardEncryptionHandler();
  encrypt.setAcrobatXLevel(encrypt.PRINT_NONE, encrypt.EXTRACT_ALL, encrypt.CHANGE_ALL, true);
  pdf.setEncryptionHandler(encrypt);

    For reading a document with a password, the PDFReader class has a convenience method whereby a password can be passed in as a String to decrypt. However, if you wanted to pass in an EncryptionHandler that would have the same result, you could do this: 

      StandardEncryptionHandler encrypt = new StandardEncryptionHandler();
  encrypt.setUserPassword("secret");
  PDFReader reader = new PDFReader(inputstream, encrypt);
  inputstream.close();
  PDF pdf = new PDF(reader);
    Since:
    2.0
    See Also:
    PDF.setEncryptionHandler(org.faceless.pdf2.EncryptionHandler), PDFReader(InputStream,EncryptionHandler)

    • Constructor Detail

      • StandardEncryptionHandler

        public StandardEncryptionHandler()
        Create a new StandardEncryptionHandler for encryption or decryption of documents. The default access level is 40-bit RC4 encryption with everything allowed (ie. the same as calling setAcrobat3Level(true,true,true,true))
        Since:
        2.0

      • StandardEncryptionHandler

        public StandardEncryptionHandler​(String password)
        Create a new StandardEncryptionHandler with the password specified. Calls the no-argument constructor and then setUserPassword(java.lang.String).
        Parameters:
        password - the password
        Since:
        2.26

    • Method Detail

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object

      • setOwnerPassword

        public void setOwnerPassword​(String password)

        Set the "security" password for the PDF document - the password required to change the security settings of the document (the access level and the open password). If you don't anticipate changing the security settings at a later date, you can leave this blank.

        Since:
        2.0

      • setUserPassword

        public void setUserPassword​(String password)
        Set the password required to open the document (also called the "User" password). It can be left blank, in which case anyone can open the document with out a password
        Since:
        2.0

      • setAcrobat3Level

        public void setAcrobat3Level​(boolean print,
                             boolean annotations,
                             boolean extraction,
                             boolean change)
        Set the access levels for Acrobat 3 and greater. The document will be encrypted using 40-bit RC4 encryption, so that any browser after Acrobat 3 can open the document.
        Parameters:
        print - true if the document can be printed
        annotations - true if form field and other annotations can be added or edited
        extraction - true if text and images can be copied from the document
        change - true if the document can have pages added, deleted, reordered or rotated
        Since:
        2.0

      • setAcrobat9Level

        @Deprecated
public void setAcrobat9Level​(int print,
                             int extraction,
                             int change,
                             boolean encryptmetadata)
                      throws NoSuchAlgorithmException
        Deprecated.
        the encryption algorithm used by Acrobat 9 has ben found to be less secure than the algorithm used by Acrobat 7, so as of 2.11.19 a request for Acrobat 9 encryption will fall back to Acrobat 7 encryption.

        Set the access levels for Acrobat 9 and greater. Acrobat 9 encryption is identical to Acrobat 7 except that the key length for the AES block cipher is 256 bit rather than 128. Documents encrypted this way can only be opened with Acrobat 9.0 or later.

        Users of Sun JVMs will require the "unlimited strength" policy files to use AES256 encryption, and other JVMs may have similar requirements.

        Parameters:
        print - one of PRINT_NONE PRINT_LOWRES PRINT_HIGHRES
        extraction - one of EXTRACT_NONE EXTRACT_ACCESSIBILITY EXTRACT_ALL
        change - one of CHANGE_NONE CHANGE_LAYOUT CHANGE_FORMS CHANGE_ANNOTATIONS CHANGE_ALL
        encryptmetadata - whether to encrypt the XMP metadata
        Throws:
        NoSuchAlgorithmException - if the AES cipher isn't available
        Since:
        2.11

      • getVersion

        public int getVersion()
        Return the version of the encryption algorithm used.
        Returns:
        1 for 40-bit RC4 as used by Acrobat 3 and later, 2 for 128-bit RC4 as used by Acrobat 5 and later, or 4 for the variant in Acrobat 6 or later and 5 for the variant in Acrobat 9 or later.
        Since:
        2.0

      • isOwnerPasswordKnown

        public boolean isOwnerPasswordKnown()
        Return true if the Owner password was used to open this PDF, false if the User password was used.
        Since:
        2.11.8

      • isMetadataEncrypted

        public boolean isMetadataEncrypted()
        Description copied from class: EncryptionHandler
        This method returns true if XMP MetaData should be stored encrypted, or false otherwise. The default implementation returns true, subclasses should override as necessary.
        Overrides:
        isMetadataEncrypted in class EncryptionHandler

      • isStreamEncrypted

        public boolean isStreamEncrypted()
        Description copied from class: EncryptionHandler
        This method returns true if Streams in the document should be stored encrypted. By default this method returns true.
        Overrides:
        isStreamEncrypted in class EncryptionHandler

      • isStringEncrypted

        public boolean isStringEncrypted()
        Description copied from class: EncryptionHandler
        This method returns true if Strings in the document should be stored encrypted. By default this method returns true.
        Overrides:
        isStringEncrypted in class EncryptionHandler

      • isEmbeddedFileEncrypted

        public boolean isEmbeddedFileEncrypted()
        Description copied from class: EncryptionHandler
        This method returns true if Embedded Files in the document should be stored encrypted. By default this method returns true.
        Overrides:
        isEmbeddedFileEncrypted in class EncryptionHandler

      • hasRight

        public boolean hasRight​(String right)
        Description copied from class: EncryptionHandler
        Returns true if the EncryptionHandler wil grant the specified right to the PDF library. The default implementation of this method returns true, but subclasses will override this method based on the rights applied to the document. This method should always return super.hasRight() if it doesn't recognise the value of "right"
        Overrides:
        hasRight in class EncryptionHandler
        Parameters:
        right - an interned() String defining the usage right the PDF library is querying.

      • getFilterName

        public String getFilterName()
        Description copied from class: EncryptionHandler
        Return the name of the "Filter" field in the Encryption dictionary. This is used to determine whether an appropriate filter has been supplied by the decryption process. For example, the StandardEncryptionHandler class returns "Standard" from this method.
        Specified by:
        getFilterName in class EncryptionHandler

      • getSubFilterName

        public String getSubFilterName()
        Description copied from class: EncryptionHandler
        Return the name of the "Subfilter" field in the Encryption dictionary. This is used to determine whether an appropriate filter has been supplied by the decryption process. As "Subfilter" is an optional field, this method may return null.
        Specified by:
        getSubFilterName in class EncryptionHandler

      • getDescription

        public String getDescription()
        Return a textual description of the algorithm used
        Since:
        2.8.2

      • isRequired

        public boolean isRequired()
        Description copied from class: EncryptionHandler
        This method should return true if the document needs to be encrypted. For example, the StandardEncryptionHandler returns false here if and only if no passwords are set and the document is set to allow full access.
        Specified by:
        isRequired in class EncryptionHandler

      • getDecryptedStreamLength

        public int getDecryptedStreamLength​(int len)
        Description copied from class: EncryptionHandler
        Return the length that an encrypted stream o the specified length would be after decryption. Generally this will be the same as the input length, which is what this method returns unless overridden. However for some encryption algorithms like AES the size will be altered. If an exact number is known this method should return it, or if it's not possible to deduce the decrypted length from the input length this method should return -1.
        Overrides:
        getDecryptedStreamLength in class EncryptionHandler

      • getEncryptedStreamLength

        public int getEncryptedStreamLength​(int len)
        Description copied from class: EncryptionHandler
        Return the length that a stream of the specified length would be after encryption. Generally this will be the same same as the input length (and that's what this method returns, unless overridden), but for some Encryption algorithms like AES, the size may be rounded up to the nearest block size.
        Overrides:
        getEncryptedStreamLength in class EncryptionHandler

      • prepareToDecrypt

        public void prepareToDecrypt()
                      throws IOException
        Description copied from class: EncryptionHandler
        This method is called just before the PDF is read in. It is expected that this method will read various parameters from the Encrypt dictionary by way of the various get... methods, and use them and the value of EncryptionHandler.getFileId() to set its internal state so that it's ready to start decryption. It may throw an IOException if these parameters are invalid, in which case the document cannot be read.
        Specified by:
        prepareToDecrypt in class EncryptionHandler
        Throws:
        IOException

      • prepareToEncrypt

        public void prepareToEncrypt()
                      throws IOException
        Description copied from class: EncryptionHandler
        This method is called when the PDF is about to be written out. It is expected that this method will write various parameters which have been set by the user to the Encrypt dictionary (including the "Filter" field) by way of the various put... methods, and will use these and the value of EncryptionHandler.getFileId() to set its internal state so that it's ready to start encryption. It may throw an IOException if these parameters are in any way invalid, in which case the document cannot be written.
        Specified by:
        prepareToEncrypt in class EncryptionHandler
        Throws:
        IOException

      • finishedEncrypt

        public void finishedEncrypt()
        Description copied from class: EncryptionHandler
        This method is called after the PDF has been written. It may be used to clean up any internal state that needs to be cleaned.
        Specified by:
        finishedEncrypt in class EncryptionHandler

      • finishedDecrypt

        public void finishedDecrypt()
        Description copied from class: EncryptionHandler
        This method is called after the PDF has been read. It may be used to clean up any internal state that needs to be cleaned.
        Specified by:
        finishedDecrypt in class EncryptionHandler