How can I disable text search on a pdf file?

Question

I just made a pdf file from the contents of a website (i.e. print->export pdf->save).

Currently, I am able to search the text. I would like to disable this option. In fact, I would like to convert this file into a pdf format which is impossible to text search.

How can I do this?

Answer 1

As long as you stay in PDF format I guess that disabling text search is not possible. But you could do the following:

1. Extract PDF pages as images
2. Recreate a PDF based on the images

Depending on the OS you use, there are different tools that can do that. Under Linux for example there is the convert tool from the ImageMagick package that could do that.

EDIT: Based on the fact that the convert tool seems to be available under Windows (thanks for the hint @moonpoint) I will add the commands I would use with convert to achieve the extraction and recreation (please note that this is the Linux command syntax which should either be identical or at least similar to the syntax in Windows):

1. convert YourFile.pdf YourFile.png # Extract the pages as images
2. convert YourFile-*.png YourNewFile.pdf # Recreate a PDF from the images

Answer 2

Disabling text search inside PDF is not possible.

One option available for you is to render them as images.

But if you are doing this to stop piracy or infringement, you should consider disabling copy paste & printing.

Instructions below

Answer 3

There is another option: scramble the font encoding. I mean, scramble the glyph codes in a font embedded into the pdf (and replace the source text with a scrambled text accordingly). Any copy-paste tool in any PDF viewer will grab rubbish...

The benefits of this method:

• size of the PDF file is not increased,
• visual quality of the document is not degraded,
• works with any PDF viewer.

There is a paper which discusses this idea including tools: http://dx.doi.org/10.13140/RG.2.1.4509.8489

(or check this post: https://groups.google.com/forum/#!topic/pdfnet-sdk/luWQmyhRDTw)