Package com.sun.pdfview.decrypt

Class PDFDecrypterFactory

java.lang.Object

com.sun.pdfview.decrypt.PDFDecrypterFactory

public class PDFDecrypterFactory
extends Object

Produces a PDFDecrypter for documents given a (possibly non-existent) Encrypt dictionary. Supports decryption of versions 1, 2 and 4 of the password-based encryption mechanisms as described in PDF Reference version 1.7. This means that it supports RC4 and AES encryption with keys of 40-128 bits; esentially, password-protected documents with compatibility up to Acrobat 8.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	CF_IDENTITY	The name of the standard Identity CryptFilter
private static final int	DEFAULT_KEY_LENGTH	Default key length for versions where key length is optional

Constructor Summary

Constructors

Constructor	Description
PDFDecrypterFactory()

Method Summary

Modifier and Type	Method	Description
private static PDFDecrypter	createCryptFilterDecrypter(PDFObject encryptDict, PDFObject documentId, PDFPassword password, int v)	Create a decrypter working from a crypt filter dictionary, as in version 4 encryption
static PDFDecrypter	createDecryptor(PDFObject encryptDict, PDFObject documentId, PDFPassword password)	Create a decryptor for a given encryption dictionary.
private static PDFDecrypter	createStandardDecrypter(PDFObject encryptDict, PDFObject documentId, PDFPassword password, Integer keyLength, boolean encryptMetadata, StandardDecrypter.EncryptionAlgorithm encryptionAlgorithm)	Create a standard single-algorithm AES or RC4 decrypter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

CF_IDENTITY

public static final String CF_IDENTITY

The name of the standard Identity CryptFilter

See Also:

• Constant Field Values

DEFAULT_KEY_LENGTH

private static final int DEFAULT_KEY_LENGTH

Default key length for versions where key length is optional

See Also:

• Constant Field Values

Constructor Details

PDFDecrypterFactory

public PDFDecrypterFactory()

Method Details

createDecryptor

public static PDFDecrypter createDecryptor(PDFObject encryptDict,
 PDFObject documentId,
 PDFPassword password)
                                    throws IOException,
EncryptionUnsupportedByPlatformException,
EncryptionUnsupportedByProductException,
PDFAuthenticationFailureException

Create a decryptor for a given encryption dictionary. A check is immediately performed that the supplied password decrypts content described by the encryption specification.

Parameters:

encryptDict - the Encrypt dict as found in the document's trailer. May be null, in which case the IdentityDecrypter will be returned.

documentId - the object with key "ID" in the trailer's dictionary. Should always be present if Encrypt is.

password - the password to use; may be null

Returns:

The decryptor that should be used for all encrypted data in the PDF

Throws:

IOException - will typically be a PDFParseException, indicating an IO problem, an error in the structure of the document, or a failure to obtain various ciphers from the installed JCE providers

EncryptionUnsupportedByPlatformException - if the encryption is not supported by the environment in which the code is executing

EncryptionUnsupportedByProductException - if PDFRenderer does not currently support the specified encryption

PDFAuthenticationFailureException - if the supplied password was not able to

createCryptFilterDecrypter

private static PDFDecrypter createCryptFilterDecrypter(PDFObject encryptDict,
 PDFObject documentId,
 PDFPassword password,
 int v)
                                                throws PDFAuthenticationFailureException,
IOException,
EncryptionUnsupportedByPlatformException,
EncryptionUnsupportedByProductException

Create a decrypter working from a crypt filter dictionary, as in version 4 encryption

Parameters:

encryptDict - the Encrypt dictionary

documentId - the document ID

password - the provided password

v - the version of encryption being used; must be at least 4

Returns:

the decrypter corresponding to the scheme expressed in encryptDict

Throws:

PDFAuthenticationFailureException - if the provided password does not decrypt this document

IOException - if there is a problem reading the PDF, an invalid document structure, or an inability to obtain the required ciphers from the platform's JCE

EncryptionUnsupportedByPlatformException - if the encryption is not supported by the environment in which the code is executing

EncryptionUnsupportedByProductException - if PDFRenderer does not currently support the specified encryption

createStandardDecrypter

private static PDFDecrypter createStandardDecrypter(PDFObject encryptDict,
 PDFObject documentId,
 PDFPassword password,
 Integer keyLength,
 boolean encryptMetadata,
 StandardDecrypter.EncryptionAlgorithm encryptionAlgorithm)
                                             throws PDFAuthenticationFailureException,
IOException,
EncryptionUnsupportedByPlatformException,
EncryptionUnsupportedByProductException

Create a standard single-algorithm AES or RC4 decrypter. The Encrypt dictionary is used where possible, but where different encryption versions employ different mechanisms of specifying configuration or may be specified via a CF entry (e.g. key length), the value is specified as a parameter.

Parameters:

encryptDict - the Encrypt dictionary

documentId - the document ID

password - the password

keyLength - the key length, in bits; may be null to use a default

encryptMetadata - whether metadata is being encrypted

encryptionAlgorithm - , the encryption algorithm

Returns:

the decrypter

Throws:

PDFAuthenticationFailureException - if the provided password is not the one expressed by the encryption dictionary

IOException - if there is a problem reading the PDF content, if the content does not comply with the PDF specification

EncryptionUnsupportedByPlatformException - if the encryption is not supported by the environment in which the code is executing

EncryptionUnsupportedByProductException - if PDFRenderer does not currently support the specified encryption