Is the PDF digital signature for a page or for an entire document? Can a page be signed?

Although the signature is generally put on a particular page of the file, the whole document is in fact signed. Nevertheless, PDF format supports so-called ‘incremental updating’ strategy that permits to add pages to the file without revoking the existing signatures (and e.g. Adobe Reader has the ability of revealing the piece of file covered by the signature, even if it was updated after the signature has actually been developed).

If you write your own PDF signer and validator you can carry out the reasoning that signs a single page. All the tools that sign PDF files will constantly sign the file, not a specific page in a document.

We are constructing a Java website to share documents with users.

Once a user access to his documents, he can digitally sign pdf with his certificate (It is stored on client-side).

The requirement is an online indication with a “sign button” on the files list.

We looked into methods to accomplish the requirement but apparently, there is not a method to do that without utilizing Java Applet or a secured server that consists of the users certificates.

We understand exactly what other option would be usage Itext on a stand-alone Java Application but that is not an online service.

The concern is:

Exists a method to access to the user’s key-store or load the certificate from the file system on the indication procedure without usage an applet?

It is not possible to utilize a certificate set up on system/browser keystore utilizing javascript due to security constraints

An alternative service is to install on the client an application with an embedded web server and send the file from the website to be signed at the minute. This application can utilize the keystore and include the itext library.

If the user has a certificate file (. p12/. pfx) it is possible to load the content using WebCryptographyApi and sign the file in customer side (without uploading certificate to server.

You can in web browser usage WebCrypto with a library like PKIjs pack a key into the web browser and sign with it, you can likewise validate the PDFs signature if you like. Here are some related examples: https://pkijs.org/examples/PDFexample.html

I’m utilizing the HTML to PDF converter tool from Winnovative to transform a HTML to a PDF with a tabulation. I did this utilizing the code below:

This works extremely well but the requirement is to likewise sign the PDF file which will be dispersed as part of our software using a digital certificate I can export from our IIS server. How can I do this?

Initially, from IIS you have to export a certificate including both public and private secrets in a password protected PFX file. The you can use to file to sign the developed PDF file

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