$self->{keylength} = 128

CAM::PDF::Decrypt

sub set_passwords { my $self = shift; my $doc = shift; my $opass = shift; my $upass = shift; my $p = shift || $self->{P} || $self->encode_permissions(1,1,1,1); require Digest::MD5; require Crypt::RC4; $doc->clean(); # Mark EVERYTHING changed # if no crypt block, create it and a trailer entry # changed V from 1 to 2 and added Length node my $cryptkeylength = 128; my $dict = CAM::PDF::Node->new('dictionary', { Filter => CAM::PDF::Node->new('label', 'Standard'), V => CAM::PDF::Node->new('number', 2), Length => CAM::PDF::Node->new('number', $cryptkeylength), R => CAM::PDF::Node->new('number', 2), P => CAM::PDF::Node->new('number', $p), O => CAM::PDF::Node->new('string', q{}), U => CAM::PDF::Node->new('string', q{}) }); my $objnode = CAM::PDF::Node->new('object', $dict); my $objnum = $self->{EncryptBlock}; if ($objnum) { $doc->replaceObject($objnum, undef, $objnode, 0); } else { $objnum = $doc->appendObject(undef, $objnode, 0); } if (!$doc->{trailer}) { die 'No trailer'; } # This may overwrite an existing ref, but that's no big deal, just a tiny bit inefficient $doc->{trailer}->{Encrypt} = CAM::PDF::Node->new('reference', $objnum); # if no ID, create it if (!$doc->{ID}) { $doc->createID(); #print 'new ID: ' . unpack('h*',$doc->{ID}) . ' (' . length($doc->{ID}) . ")\n"; } #else { print 'old ID: '.unpack('h*',$doc->{ID}) . ' (' . length($doc->{ID}) . ")\n"; } # Recompute O and U # To do so, we must set up a couple of dependent variables first: $self->{R} = 2; $self->{keylength} = $cryptkeylength; $self->{P} = $p; # set O (has to be first because U uses O) $self->{O} = $self->_compute_o($opass, $upass); # set U $self->{U} = $self->_compute_u($doc->{ID}, $upass); # save O and U in the Encrypt block $dict = $doc->getObjValue($objnum); $dict->{O}->{value} = $self->{O}; $dict->{U}->{value} = $self->{U}; # Create a brand new instance my $pkg = ref $self; $doc->{crypt} = $pkg->new($doc, $opass, $upass, 0) || die "$CAM::PDF::errstr\n"; return $doc->{crypt}; }