Why Encrypt a PDF?
The portable nature of PDF files means that they can easily be lost. Whether you have sensitive PDFs stored on a mobile device, some sort of portable Flash Drive or even if you have emailed one to the wrong recipient, there is a strong case for encrypting any sensitive information stored in this format.
You can easily set a password in Adobe Acrobat in order to protect your document but this may only turn out to be a temporary measure – standard passwords can be bypassed.
As such you should consider enhancing the protection offered by a standard password by employing some 128 bit PDF encryption. This functionality is available in the expensive Adobe software but not in free PDF generating applications or in Microsoft Word 2010.
(Image via wikipedia.org)
Top 128 Bit PDF Encryption Software
Various PDF encryption options are available and here are three of the best: VeryPDF, PDF-Convert and A-PDF.
Using 40-bit or 128-bit encryption to apply passwords and set permissions to existing PDFs, VeryPDF can be used to prevent printing of documents by unauthorized readers, although the source document must be an unencrypted PDF. Copying of text and graphics within the PDF document can also be blocked, making VeryPDF a good choice with plenty of options.
Licenses for VeryPDF begin at $38.00, with lower prices available for bulk licensing. Visit www.verypdf.com/encryptpdf for more information.
PDF Encrypt Tool v2.00
An alternative to VeryPDF is PDF Encrypt Tool, which also supports 40-bit and 128-bit encryption. Again offering passwords that can prevent printing of the document, this particular utility is particularly flexible in terms of your operating system - you can even install it on a Windows 95 computer providing the PC has over 32MB of memory.
A trial version of PDF Encrypt Tool is available for you to try out, allowing up to 30 encryptions. Visit www.pdf-convert.com/pdf-encrypt-tool/index.htm to download or purchase for $29.35.
Making full use of the fact that A-PDF will encrypt a document for a fraction of the price of the full Adobe Acrobat software, A-PDF includes support for 40-bit and 128-bit encryption, user accounts and specific permissions. Additionally, documents can be set to expire after a pre-determined period of time.
A trial version of A-PDF is available free from the website at www.a-pdf.com/security/password.htm, while a full license can be purchased for $27.
Back to Adobe Acrobat
If all of this seems like overkill and you would like to stick with the basic password functions in Adobe Acrobat, this can be set up in the Document > Security > Restrict opening & Editing > Password Security – Settings window.
Select Require password to open document and enter a password of your choice, and then confirm it. Finally, click on OK to exit the window and go to File > Save or File Save as… to save your PDF document with the encrypted password.
(Note that these steps are for Adobe Acrobat 2008; however the steps in later versions are quite similar.)