Remove erroneous handling of /EFF for stream decryption

I thought /EFF was supposed to be used as a default for decrypting
embedded file streams, but actually it's supposed to be advice to a
conforming writer about handling new ones. This makes sense since the
findAttachmentStreams code, which is not actually needed, was never
right.

1 files changed, 15 insertions, 10 deletions

diff --git a/libqpdf/QPDF_encryption.cc b/libqpdf/QPDF_encryption.cc
index 00bd697e..2ff48df9 100644
--- a/libqpdf/QPDF_encryption.cc
+++ b/libqpdf/QPDF_encryption.cc
@@ -1022,6 +1022,20 @@ QPDF::initializeEncryption()
 	this->m->encp->cf_string = interpretCF(this->m->encp, StrF);
 	if (EFF.isName())
 	{
+            // qpdf does not use this for anything other than
+            // informational purposes. This is intended to instruct
+            // conforming writers on which crypt filter should be used
+            // when new file attachments are added to a PDF file, but
+            // qpdf never generates encrypted files with non-default
+            // crypt filters. Prior to 10.2, I was under the mistaken
+            // impression that this was supposed to be used for
+            // decrypting attachments, but the code was wrong in a way
+            // that turns out not to have mattered because no writers
+            // were generating files the way I was imagining. Still,
+            // providing this information could be useful when looking
+            // at a file generated by something else, such as Acrobat
+            // when specifying that only attachments should be
+            // encrypted.
 	    this->m->encp->cf_file = interpretCF(this->m->encp, EFF);
 	}
 	else
@@ -1224,7 +1238,6 @@ QPDF::decryptStream(PointerHolder<EncryptionParameters> encp,
                     QPDF& qpdf_for_warning, Pipeline*& pipeline,
                     int objid, int generation,
 		    QPDFObjectHandle& stream_dict,
-                    bool is_attachment_stream,
 		    std::vector<PointerHolder<Pipeline> >& heap)
 {
     std::string type;
@@ -1296,15 +1309,7 @@ QPDF::decryptStream(PointerHolder<EncryptionParameters> encp,
 	    }
 	    else
 	    {
-                if (is_attachment_stream)
-                {
-                    QTC::TC("qpdf", "QPDF_encryption attachment stream");
-                    method = encp->cf_file;
-                }
-                else
-                {
-                    method = encp->cf_stream;
-                }
+                method = encp->cf_stream;
 	    }
 	}
 	use_aes = false;