Fujitsu ScanSnap S1500 – Paperless Workflow (Part 2) – 128-bit AES Encryption

Here is part 2 of my paperless workflow. Part 1 is here.

As discussed earlier, ScanSnap can password protect any PDF files scanned but the password strength is limited to 40-bit RC2. This is a good encryption strength for “most” PDF files but you will need to know the limitations of PDF password encryption. Here is a good reference guide to get you going.

The bottom line is this: Please don’t have a false expectation that any form of PDF password protection is crack proof (nothing is nowadays). There are always password decryption tools available, using all sort of intelligence to crack that PDF file. If all else fail, a brute force method is usually applied. So if you have a top secret document (the type typically associated with FBI agents and CIA operatives) that you want protected, protecting these files using any form of PDF password protection may not work very well for you.

Having said this, protecting important files with 128-bit AES can be beneficial at times. Make sure you use a strong password. Even if someone tried to hack that file using a password decryption tool, a brute force method will usually take some time to complete (sometimes this take days or weeks), making the process much more inconvenient for prying eyes. The primary reason I password protect my document is to deter identity theft. As mentioned, there is only a limit of what you can do to protect your files so you need to be sensible about the kind of sensitive documents you have.

If I am converting a book into digital PDF format, I won’t bother to password protect it. If I am digitizing a receipt of something I bought from K-Mart, I won’t bother to password protect it either. But If I am digitizing a mobile phone bill, I will want to password protect it. You get what I mean.

Okay. So I have established that ScanSnap can’t do anything better than 40-bit RC2. If you know a way to do this otherwise, please please please let me know. I hope future versions of the Fujitsu software will get this updated.

The workaround I found is to use another software that is capable of password protecting pdf files. For this task, I cannot think of any other software better than PDFTK. PDFTK is described as an electronic staple-remover, hole-punch, binder, secret-decoder-ring, and X-Ray-glasses for PDF files. I must agree that PDFTK is the ultimate swiss army knife utility for PDF files. I cannot recommend this software enough. PDFTK is a command line utility (which might deter some users) but there are GUI frontend tools available for PDFTK (such as PDFTK4ALL) and I am personally very fond of PDFTK4ALL.

You can download PDFTK4ALL here. The package includes the PDFTK command line utility so installing PDFTK4ALL will also get PDFTK installed correctly. Installing PDFTK4ALL is very simple so I won’t delve into this here. The idea is to use PDFTK4ALL to process whatever files scanned and encrypt them accordingly.

To understand the process better, it is important to know that by default, ScanSnap will dump all newly scanned files into the root directory of the “ScanSnap Folder”. You can set this folder by launching ScanSnap Organizer -> click on the top left big application button -> click on the “options” button and you will find a text field where you can input the folder location of your choice.

From the above screenshot, it can be observed that my ScanSnap folder is set as “D:\#PERSONAL_FILE_STORAGE\”. You can set any folder really.

In addition, I setup an “INBOX” folder so that whatever PDF files that are “post-processed” can be deposited into this INBOX folder. Note that there is a “#” symbol in front of the inbox folder. This is intentional as this will force the #INBOX folder to appear as the first entry in ScanSnap Organizer, as follows:

Now that the ScanSnap folder and the INBOX folders are setup correctly, we can start to use PDFTK4ALL. Once PDFTK4ALL is loaded, press the “Add” button to add new PDF files that are newly added to the ScanSnap folder.

Set the output directory to the new INBOX folder we have created earlier.

Now click the “Encryption” button. This dialog box will pop up. Make sure you click 128 bit encryption and use a strong password. Make sure that this password is the SAME password as the password you have created earlier in ScanSnap Manager. See picture below. If the password you use in PDFTK4ALL is different to that previously set in ScanSnap Manager, the thumbnails of these PDF files will not be visible in ScanSnap Organizer.

After this, press the “Go!” button and PDFTK4ALL will process all the PDF files in the queue and put the processed files in the INBOX folder.

Now if you go back to ScanSnap Organizer, you will now find these PDF files showed up in the #INBOX folder and you can then move them to whatever sub-folders you like or proceed with any other post-processing you want.

You will be able to observe that the PDF files you encrypted using PDFTK4ALL is visible in ScanSnap Organizer (the “lock” symbol tells you that the PDF is password protected). This is a very good feature of ScanSnap Organizer that I have grown to appreciate. Without this feature, you will need to enter the password to each and every encrypted PDF document just to have a peek of its content.

Now if you load the newly encrypted document in Adobe Acrobat, you will be able to inspect the encryption level of the document. Just go to File -> Properties -> Security -> Show Details.

So with the help of PDFTK and a wonderful GUI (PDFTK4ALL), we can further enhance the productivity of the ScanSnap scanner.

I hope this post is helpful.


Posted on April 8, 2012, in Fujitsu ScanSnap S1500, Going Paperless. Bookmark the permalink. 4 Comments.

  1. Hi Joseph! Thank you VERY much for Part 2. It was worth the wait! You have really got me thinking about this. I might re-think my paperless strategy a bit. I know I won’t go to the effort of protecting my documents like this but, on the other hand, I don’t want to expose myself to any risks. I am thinking what I might do is elect to receive all bills online (all that can be, at least) – this will reduce my paper a little. I’m thinking I’ll still get the ScanSnap and use it for all of the other paper we receive (e.g. parenting info, product info, receipts) that takes up space. What do you think?

  2. Yes. That would be a good strategy in my opinion. A lot of my bills are also received online…e.g. my broadband bill, my cellphone bills, etc. For these, I usually download them to my local drive where I keep them for offline record. For other papers we scattered around the house (receipts, catalogues, flyers, etc) that are worth keeping, I will scan those using scansnap and if they are not legal documents (or tax related documents), I will chuck away the originals.

  3. Thanks Joseph! I really appreciate your time and the info in your posts. It is so helpful. I’ll let you know how I go.

  4. unfortunately the pdf encryption tool runs only on windows PCs, so mac users will have to look elsewhere ;(

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