SECTION 8.7
729
Digital Signatures
KEY
TYPE
VALUE
V
integer
(Optional; PDF 1.5)
The version of the signature dictionary format. It corre-
sponds to the usage of the signature dictionary in the context of the value of
SubFilter
. The value is 1 if the
Reference
dictionary is considered critical to
the validation of the signature.
Default value: 0.
Prop_Build
dictionary
(Optional; PDF 1.5)
A dictionary that can be used by a signature handler to
record information that captures the state of the computer environment used
for signing, such as the name of the handler used to create the signature, soft-
ware build date, version, and operating system.
Adobe publishes a separate specification, the
PDF Signature Build Dictionary
Specification for Acrobat 6.0
that provides implementation guidelines for the
use of this dictionary.
Prop_AuthTime
integer
(Optional; PDF 1.5)
The number of seconds since the signer was last authen-
ticated. It is intended to be used in claims of signature repudiation. It should
be omitted if the value is unknown.
(Optional; PDF 1.5)
The method used to authenticate the signer. It is intend-
ed to be used in claims of signature repudiation. Valid values include
PIN
,
Password
, and
Fingerprint
.
Prop_AuthType
name
Note:
The entries in the signature dictionary can be conceptualized as being in dif-
ferent dictionaries; they are in one dictionary for historical and cryptographic rea-
sons. The categories are signature properties (
R
,
M
,
Name
,
Reason
,
Location
,
Prop_Build
,
Prop_AuthTime
, and
Prop_AuthType
); key information (
Cert
and por-
tions of
Contents
when the signature value is a PKCS#7 object); reference
(
Reference
and
ByteRange
); and signature value (
Contents
when the signature val-
ue is a PKCS#1 object).