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Adobe Acrobat SDK
Adobe® Supplement to the ISO 32000
Algorithm 3.1a Encryption of data using the AES algorithm
1. Use the 32-byte file encryption key for the AES-256 symmetric key algorithm, along with the string or
stream data to be encrypted.
Use the AES algorithm in Cipher Block Chaining (CBC) mode, which requires an initialization vector. The
block size parameter is set to 16 bytes, and the initialization vector is a 16-byte random number that is
stored as the first 16 bytes of the encrypted stream or string.
The output is the encrypted data to be stored in the PDF file.
3.5.2 Standard Security Handler
Revise the first paragraph on page 122 to read as follows.
If
revision version 4 or 5
"Crypt Filters"). The support is limited to the
whose dictionaries contain
StdCF
version 4, the filter
be
AESV3
Standard Encryption Dictionary
Table 3.19 shows the encryption dictionary entries for the standard security handler (in addition to those
in Table 3.18).
Add three new entries,
content is shown in gray.
TABLE 3.19 Additional encryption dictionary entries for the standard security handler
KEY
R
is specified, the standard security handler supports crypt filters (see Section 3.5.4,
value may be
CFM
(AES-256).
,
and
OE
UE
Perms
TYPE
number
crypt filter (see Table 3.23) and crypt filters named
Identity
a
value of
or
CFM
V2
AESV2
(RC4) or
(AES-128). For version 5, the filter
V2
AESV2
, to Table 3.19, and modify the other entries as shown. Unchanged
VALUE
(Required) A number specifying which revision of the
standard security handler should be used to interpret this
dictionary:
if the document is encrypted with a
2
●
(see Table 3.18) and does not have any of the access
2
permissions set (by means of the P entry, below) that
are designated "Revision 3 or greater" in Table 3.20
if the document is encrypted with a
3
●
or has any "Revision 3 or greater" access permissions
set
if the document is encrypted with a
4
●
(ExtensionLevel 3) if the document is encrypted with a
5
●
value of
V
Syntax (Chapter 3 in PDF Reference)
3.5.2 Standard Security Handler
and
an
AuthEvent
5
16
value of
.
For
DocOpen
value shall
CFM
value less than
V
value of
or
,
V
2
3
value of 4
V
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