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Syntax (Chapter 3 in PDF Reference)
This section describes extensions to the PDF specification contained in the PDF Reference, sixth edition,
version 1.7 and in ISO 32000 (Document management - Portable document format - PDF 1.7). The latter
document is the version of the PDF specification that has been ratified by the ISO. These documents differ
as described in About the ISO Draft of the PDF 1.7 Reference.
Note:
This guide uses italics to identify information not intended for inclusion in the PDF specification. For
convenience, the phrase BaseVersion 1.7, Adobe ExtensionLevel 3 is shortened to ExtensionLevel 3
throughout this document.
3.5 Encryption
On page 116, modify the paragraph as shown below where unchanged content is shown in gray.
The
entry, in specifying which algorithm to use, determines the length of the encryption key, on which
V
the encryption (and decryption) of data in a PDF file is based. For
specifies the exact length of the encryption key. In PDF 1.5, a value of 4 for V permits the security handler
to use its own encryption and decryption algorithms and to specify crypt filters
bits (16 bytes)
for
permits the specification of crypt filters with a key length of 256 bits (32 bytes).
5
V
to use on specific streams (see Section 3.5.4, "Crypt Filters").
values 2 and 3, the
V
Length
with a key length of 128
For extension level 3, a value of
entry
13
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