Mick It is not possible to change a PDF without invalidating its signature, except to fill in forms or add comments.
If you have access to the certificate that was used to sign the original PDF file then you can re-sign the PDF file after you have modified it. I believe that there are people doing this with PDFBox, though I am not one of them. If you do not have access to the certificate then there is nothing that can be done. -- John On 1 Feb 2014, at 13:28, Michael Uberti <[email protected]> wrote: >>> I have an issue here and was wondering if I could get some help here. >>> If anyone could offer some help with my start up business, I am happy to >>> pay for the service if required. I am really stuck here. Andreas Lehmkühler >>> has already offered some support and suggested I post this to the >>> developers. >>> >>> We have a form created with Adobe Acrobat that is for sale via an opencart >>> shopping cart. (commonwealth bank) >>> >>> http://www.oceantimemarine.com/download.html >>> >>> The functionality that we want is to be able to write to the PDF >>> (watermarking >>> or to specific form fields) at point of sale without affecting the Adobe >>> signed certificate required to then open the PDF and retain the form >>> functionality in Adobe Reader once purchased. >>> >>> So far I have tried PDFtk and FPDF plugins (among others) to watermark the >>> PDF >>> 'on the fly', which successfully watermarks the PDF after the sale and >>> before >>> the download is made available. The problem is that this requires >>> server-side >>> PHP to copy to template on the server which subsequently invalidates the >>> Adobe >>> signed certificate, rendering the form fields inoperable for use with Adobe >>> Reader. >>> >>> I have considered server generated DRM which is too expensive. I have also >>> considered rebuilding the form in PHP at point of sale, but this would be >>> too >>> time consuming because we have many thousands of form fields in the >>> document. >>> >>> Do you know of a way to get around the Adobe certificate for using server >>> generated forms to work in Adobe Reader? >>> >>> Or perhaps you know of another way the process could run to watermark or >>> write >>> to specific fields in the document without invalidating the form field >>> functionality for use in Adobe Reader? >>> >> I'm afraid neither me nor anone else can help you with that. The purpose of a >> signature is to ensure that the signed file wasn't altered. If you add a >> watermark to your pdf you have to sign it again. >> >> Maybe you can use PDFBox to sign your pdf. I'm not an expert on that topic. >> You >> should adress your question to our mailing lists. >> >>> The PDF is a document (ebook) that is a safety management system (SMS) >>> template. >>> The client purchases online and then fills in the document in the editable >>> form fields. >>> What I am trying to achieve is basically a water mark of their company name >>> once they have entered this information in the shopping cart so this is >>> like a >>> security feature and that every SMS is unique to that one company. >>> >>> Ok this is the scenario, So the customer enters their details (specifically >>> their company name) and then I'd like this information embedded in the >>> document that they are purchasing as a security feature so that the document >>> remains unique to that company. >>> This will need to happen for every new customer >>> >>> Why not Pay Pal? The reason we chose a bank (commonwealth bank Australia) >>> was >>> the security issues as trust issues by the consumer, mostly because PayPal >>> had >>> issues with paying into a unit trust, it's easier for us to use the bank, >>> the >>> issue is not the shopping cart it's actually adobe. >>> >>> If you want to call me on skype michaeluberti or +61 438527250 or email on >>> [email protected] I can make a plan with you if you think you are able >>> to do this. >>> >>> Mick >>> >>> >>> Michael Uberti >>> +61438527250 >>> >> >> >> >
