org.icepdf.core.pobjects.security

Class CryptFilterEntry

java.lang.Object

org.icepdf.core.pobjects.Dictionary

org.icepdf.core.pobjects.security.CryptFilterEntry

public class CryptFilterEntry
extends Dictionary

Individual Crypt filter definition. A filter is associated with a name key in the CryptFilter definition. A stream or string that uses a crypt filter will references it by its name.

Field Summary

Fields

Modifier and Type	Field and Description
static Name	AUTHEVENT_KEY
static Name	CFM_KEY
static Name	LENGTH_KEY
static Name	TYPE

Fields inherited from class org.icepdf.core.pobjects.Dictionary

entries, FORM_TYPE_KEY, inited, isDeleted, isNew, library, SUBTYPE_KEY, TYPE_KEY

Constructor Summary

Constructors

Constructor and Description
CryptFilterEntry(Library library, java.util.HashMap entries)

Method Summary

Modifier and Type	Method and Description
Name	getAuthEvent() The event to be used to trigger the authorization that is required to access encryption keys used by this filter.
Name	getCryptFilterMethod() The method used, if any, by the conforming reader to decrypt data.
int	getLength() (Optional) The bit length of the encryption key.
Name	getType() If present, shall be CryptFilter for a crypt filter dictionary.

Methods inherited from class org.icepdf.core.pobjects.Dictionary

getEntries, getFloat, getInt, getLibrary, getNumber, getObject, getPObjectReference, init, isDeleted, isNew, setDeleted, setNew, setPObjectReference, toString

Methods inherited from class java.lang.Object

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

Field Detail

TYPE

public static final Name TYPE

AUTHEVENT_KEY

public static final Name AUTHEVENT_KEY

CFM_KEY

public static final Name CFM_KEY

LENGTH_KEY

public static final Name LENGTH_KEY

Constructor Detail

CryptFilterEntry

public CryptFilterEntry(Library library,
                        java.util.HashMap entries)

Method Detail

getType

public Name getType()

If present, shall be CryptFilter for a crypt filter dictionary.

Returns:

dictionary type, CryptFilter

getCryptFilterMethod

public Name getCryptFilterMethod()

The method used, if any, by the conforming reader to decrypt data. The following values shall be supported:

• None - The application shall not decrypt data but shall direct the input stream to the security handler for decryption.
• V2 - The application shall ask the security handler for the encryption key and shall implicitly decrypt data with "Algorithm 1: Encryption of data using the RC4 or AES algorithms", using the RC4 algorithm.
• AESV2 - (PDF 1.6) The application shall ask the security handler for the encryption key and shall implicitly decrypt data with "Algorithm 1: Encryption of data using the RC4 or AES algorithms", using the AES algorithm in Cipher Block Chaining (CBC) mode with a 16-byte block size and an initialization vector that shall be randomly generated and placed as the first 16 bytes in the stream or string.

When the value is V2 or AESV2, the application may ask once for this encryption key and cache the key for subsequent use for streams that use the same crypt filter. Therefore, there shall be a one-to-one relationship between a crypt filter name and the corresponding encryption key.

Only the values listed here shall be supported. Applications that encounter other values shall report that the file is encrypted with an unsupported algorithm.

Default value: None.

Returns:

name of crypt filter method.

getAuthEvent

public Name getAuthEvent()

The event to be used to trigger the authorization that is required to access encryption keys used by this filter. If authorization fails, the event shall fail. Valid values shall be:

• DocOpen: Authorization shall be required when a document is opened.
• EFOpen: Authorization shall be required when accessing embedded files.

Default value: DocOpen.

If this filter is used as the value of StrF or StmF in the encryption dictionary (see Table 20), the conforming reader shall ignore this key and behave as if the value is DocOpen.

Returns:

authorization event.

getLength

public int getLength()

(Optional) The bit length of the encryption key. It shall be a multiple of 8 in the range of 40 to 128. Security handlers may define their own use of the Length entry and should use it to define the bit length of the encryption key. Standard security handler expresses the length in multiples of 8 (16 means 128) and public-key security handler expresses it as is (128 means 128).

Returns:

lenth of encryption key