"All about digital signatures in PDF"

By Ricky Snow
BCL Technologies
Issue 14 for 2007

A digital signature is placed on a PDF document as a proof of identity, identifying the person signing a document the way a handwritten signature does. But unlike conventional signatures, a digital signature also stores information about the person signing the document to ensure accountability for the signature. Furthermore, a digital signature preserves the integrity of a PDF document. It gives you the assurance that the PDF document has not been altered since the last time it was signed because any change made in a digitally signed PDF document would invalidate the digital signature. PDFs can also have multiple signatures.

So where do you start? First, you need to have a digital ID which contains your personal information. Most PDF applications, such as Nitro PDF Professional or Adobe Acrobat, have the ability to create a self-signed digital ID. You will be the owner of this digital ID, and when you sign a PDF file using this ID, other people can verify that your signature is valid by comparing it with your certificate in their list of trusted identity (you need to send them the certificate before hand). A more secure option is to acquire a digital ID from an independent security authentication company, like Verisign.

Once you have the digital ID, simply add it to your Nitro PDF Professional or Adobe Acrobat security settings. Your digital ID will be used the next time you sign a document.

If you are a developer and need to include digital signature capabilities in your application, you can use programming toolkit like BCL easyPDF SDK.

Until next time, please browse PDF Store's Security aisle for the complete range of PDF security products.

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