If you don’t want your PDF document to be copied, printed, modified or opened freely by other people, you can encrypt pdf document. So if you want to convertdocument and encrypt the output pdf document, you can use the command line application Metafile to PDF Converter Command Line as your tool.
The command line application supports the usual PDF features, including compression and 128 bit encryption and it was the first command line application to allow embedding of font subsets to reduce file size. If you want to try it, you can download the free trial version of Metafile to PDF Converter Command Line at http://www.verypdf.com/tif2pdf/image2pdf_emf2pdf_cmd.zip and unpack it to your computer. Then the executable file emf2pdf.exe will be available and it is also the called program in the conversion from .
When you want to input the command line for convertingand encrypting pdf document, you should open MS-DOS interface at first. You can click “Start”—“Run” or use the hot key “Window”+ “R” to open “Run” dialog box in which you can input “cmd” in “Open” combo box. Then please click “OK” button.
The command line to be inputted in MS-DOS interface is consisted of called program, parameter for setting password, key length, encryption standard, source file and target file. You can see the following basic command line template:
emf2pdf.exe -openpwd 234 -keylen 0 -encryption 4 C:\A.wmf C:\B.pdf
You can see the command line example below which is the specific application to the template above.
"C:\Program Files\image2pdf_emf2pdf_cmd3.2\emf2pdf.exe" -openpwd 234 -keylen 0 -encryption 4 "C:\A.wmf" C:\B.pdf
"C:\Program Files\image2pdf_emf2pdf_cmd3.2\emf2pdf.exe" is the path of called program emf2pdf.exe.
-openpwd 234 is the parameter for setting open password. The command line “-ownerpwd” can be used to set owner password.
-keylen 0 is for setting key length as 40 bit RC4 encryption.
-encryption 4 is for denying printing.
"C:\A.wmf" is the path of source file.
C:\B.pdf is the path of target file.
When you don’t want to input the file path into MS-DOS interface, you can also drag the file from its folder to the command line window and the file will instantly turn to file path.
At last, please click “Enter” button on the keyboard to run the conversion from wmf to pdf.
There are also some other commands about key length and encryption at the following website: http://www.verypdf.com/pdfcamp/rtf2pdf.html.