APPENDIX H
1122
Compatibility and Implementation Notes
143. In Adobe Reader 6.0, any usage right that permits the document to be
modified implicitly enables the
FullSave
right.
Adobe Reader 7.0 and 8.0 mimic Reader 6.0 behavior if the PDF docu-
ment contains a
UR
dictionary but omits a
UR3
dictionary. If the PDF doc-
ument contains a
UR3
dictionary, only rights specified by the
Annots
entry
that permit the document to be modified implicitly enable the
FullSave
right. For all other rights,
FullSave
must be explicitly enabled in order to
save the document. (Signature rights permit saving as part of the signing
process but not otherwise).
If the
P
entry in the
UR
transform parameters dictionary is
true
, Acrobat
7.0 and greater viewer applications permit only those rights that are en-
abled by the entries in the dictionary. However, viewers permit saving the
document as long as any rights that permit modifying the document are
enabled.
144. In Acrobat 6.0 and greater, the
DigestMethod
entry in the signature refer-
ence dictionary is required, even though this specification indicates that
entry is optional.
145. In Acrobat 6.0 and greater, the
V
entry in the various transform parame-
ters dictionaries are required, even though this specification indicates oth-
erwise. Those dictionaries include the DocMDP transform parameters
dictionary, the UR transform parameters dictionary, and the FieldMDP
transform parameters dictionary.
146. In versions earlier than Acrobat 6.0, it was a requirement that the signer’s
signature be the first certificate in the PKCS#7 object. Acrobat 6.0 re-
moved this restriction, but for maximum compatibility with earlier ver-
sions, this practice should be followed.
147. PDF 1.7 added the ability to specify requirements the PDF consumer ap-
plication must satisfy before it can process or display a PDF document.
Although Acrobat 7.0 officially supports PDF 1.6, Acrobat 7.0.5 also sup-
ports this document requirements feature.