PDF Digital Signature Validation
Did you ever receive a PDF document which is digitally signed? When you open this document in Adobe Acrobat, you'll notice that Adobe Acrobat is validating the document by showing a very small 'green checkbox' in the top left, something like this:
Ok, great, but what does it mean?
It means that this document has been 'digitally signed' or better, somebody has used 'a certificate' to perform 'a signature' on the content of a PDF document.
Hold up, what do we mean with a 'certificate' and where can I find them?
Simply put, a certificate can be seen as an electronic document which you can use to authenticate or digitally sign. A certificate contains information about an identity. You can find those certificates on EU national ID cards for example; you can buy them at from a Certificate Authority (CA), ...
Now, how does that work? And how can I validate digitally signed PDF documents using an API?
This tutorial will explain the following:
- how to validate documents in Adobe Acrobat
- how to perform the same validation of digitally signed document in your own application
For the latter, a step-by-step approach will be used. An example implementation is provided on Github:
https://github.com/Trust1Team/vwapp
The application is available online.