Key |
Type |
Value |
---|---|---|
Filter |
name |
(Required) The name of the preferred security handler for this document. It shall be the name of the security handler that was used to encrypt the document. If SubFilter is not present, only this security handler shall be used when opening the document. If it is present, a conforming reader can use any security handler that implements the format specified by SubFilter. Standard shall be the name of the built-in password-based security handler. Names for other security handlers may be registered by using the procedure described in Annex E . |
SubFilter |
name |
(Optional; PDF 1.3) A name that completely specifies the format and interpretation of the contents of the encryption dictionary. It allows security handlers other than the one specified by Filter to decrypt the document. If this entry is absent, other security handlers shall not decrypt the document. NOTE This entry was introduced in PDF 1.3 to support the use of public-key cryptography in PDF files (see 7.6.4, "Public-Key Security Handlers" ); however, it was not incorporated into the PDF Reference until the fourth edition (PDF 1.5). |
V |
number |
(Optional) A code specifying the algorithm to be used in encrypting and decrypting the document: 0 An algorithm that is undocumented. This value shall not be used. 1 "Algorithm 1: Encryption of data using the RC4 or AES algorithms" in 7.6.2, "General Encryption Algorithm," with an encryption key length of 40 bits; see below. 2(PDF 1.4) "Algorithm 1: Encryption of data using the RC4 or AES algorithms" in 7.6.2, "General Encryption Algorithm," but permitting encryption key lengths greater than 40 bits. 3(PDF 1.4) An unpublished algorithm that permits encryption key lengths ranging from 40 to 128 bits. This value shall not appear in a conforming PDF file. 4(PDF 1.5) The security handler defines the use of encryption and decryption in the document, using the rules specified by the CF, StmF, and StrF entries. The default value if this entry is omitted shall be 0, but when present should be a value of 1 or greater. |
Length |
integer |
(Optional; PDF 1.4; only if V is 2 or 3) The length of the encryption key, in bits. The value shall be a multiple of 8, in the range 40 to 128. Default value: 40. |
CF |
dictionary |
(Optional; meaningful only when the value of V is 4; PDF 1.5) A dictionary whose keys shall be crypt filter names and whose values shall be the corresponding crypt filter dictionaries (see Table 25 ). Every crypt filter used in the document shall have an entry in this dictionary, except for the standard crypt filter names (see Table 26 ). The conforming reader shall ignore entries in CF dictionary with the keys equal to those listed in Ta b l e 26 and use properties of the respective standard crypt filters. |
StmF |
name |
(Optional; meaningful only when the value of V is 4; PDF 1.5) The name of the crypt filter that shall be used by default when decrypting streams. The name shall be a key in the CF dictionary or a standard crypt filter name specified in Ta b l e 26 . All streams in the document, except for cross-reference streams (see 7.5.8, "Cross-Reference Streams" ) or streams that have a Crypt entry in their Filter array (see Table 6 ), shall be decrypted by the security handler, using this crypt filter. Default value: Identity. |
StrF |
name |
(Optional; meaningful only when the value of V is 4; PDF 1.5) The name of the crypt filter that shall be used when decrypting all strings in the document. The name shall be a key in the CF dictionary or a standard crypt filter name specified in Ta b l e 26 . Default value: Identity. |
EFF |
name |
(Optional; meaningful only when the value of V is 4; PDF 1.6) The name of the crypt filter that shall be used when encrypting embedded file streams that do not have their own crypt filter specifier; it shall correspond to a key in the CFdictionary or a standard crypt filter name specified in Table 26 . This entry shall be provided by the security handler. Conforming writers shall respect this value when encrypting embedded files, except for embedded file streams that have their own crypt filter specifier. If this entry is not present, and the embedded file stream does not contain a crypt filter specifier, the stream shall be encrypted using the default stream crypt filter specified by StmF. |