Adobe 12020596 User Guide - Page 16

Standard Security Handler

Get Adobe 12020596 PDF manuals and user guides View all Adobe 12020596 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 16 highlights

Adobe Acrobat SDK Adobe® Supplement to the ISO 32000 Syntax (Chapter 3 in PDF Reference) 3.5.2 Standard Security Handler 16 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 is specified, the standard security handler supports crypt filters (see Section 3.5.4, "Crypt Filters"). The support is limited to the Identity crypt filter (see Table 3.23) and crypt filters named StdCF whose dictionaries contain a CFM value of V2 or AESV2 and an AuthEvent value of DocOpen. For version 4, the filter CFM value may be V2 (RC4) or AESV2 (AES-128). For version 5, the filter CFM value shall be AESV3 (AES-256). 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, OE, UE and Perms, to Table 3.19, and modify the other entries as shown. Unchanged content is shown in gray. TABLE 3.19 Additional encryption dictionary entries for the standard security handler KEY TYPE VALUE R number (Required) A number specifying which revision of the standard security handler should be used to interpret this dictionary: ● 2 if the document is encrypted with a V value less than 2 (see Table 3.18) and does not have any of the access permissions set (by means of the P entry, below) that are designated "Revision 3 or greater" in Table 3.20 ● 3 if the document is encrypted with a V value of 2 or 3, or has any "Revision 3 or greater" access permissions set ● 4 if the document is encrypted with a V value of 4 ● 5 (ExtensionLevel 3) if the document is encrypted with a V value of 5

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
Adobe Acrobat SDK
Syntax (Chapter 3 in PDF Reference)
Adobe® Supplement to the ISO 32000
3.5.2 Standard Security Handler
16
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
is specified, the standard security handler supports crypt filters (see Section 3.5.4,
“Crypt Filters”). The support is limited to the
Identity
crypt filter (see Table 3.23) and crypt filters named
StdCF
whose dictionaries contain
a
CFM
value of
V2
or
AESV2
and
an
AuthEvent
value of
DocOpen
.
For
version 4, the filter
CFM
value may be
V2
(RC4) or
AESV2
(AES-128). For version 5, the filter
CFM
value shall
be
AESV3
(AES-256).
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,
OE
,
UE
and
Perms
, to Table 3.19, and modify the other entries as shown. Unchanged
content is shown in gray.
TABLE 3.19 Additional encryption dictionary entries for the standard security handler
KEY
TYPE
VALUE
R
number
(
Required
) A number specifying which revision of the
standard security handler should be used to interpret this
dictionary:
●
2
if the document is encrypted with a
V
value less than
2
(see Table 3.18) and does not have any of the access
permissions set (by means of the P entry, below) that
are designated “Revision 3 or greater” in Table 3.20
●
3
if the document is encrypted with a
V
value of
2
or
3
,
or has any “Revision 3 or greater” access permissions
set
●
4
if the document is encrypted with a
V
value of 4
●
5
(
ExtensionLevel 3
) if the document is encrypted with a
V
value of
5