Didier Stevens

Sunday 4 January 2009

Howto: Add a Digital Signature to a PDF File

Filed under: Encryption,PDF — Didier Stevens @ 21:47

After signing an executable and a Mozilla add-on, let’s sign a PDF document with our certificate.

I didn’t manage to use a free tool to sign a PDF document with a certificate, so we’ll use a trial version of Adobe Acrobat Professional.

Our PKCS12 file (with keys and signatures) is imported in our certificate store, so let’s open a PDF document and sign it:
20090104-214956

20090104-215128

20090104-215340

After signing, we notice there’s one issue, our identity is not yet trusted:

20090104-215702

Let’s trust ourself:

20090104-215955

20090104-220023

20090104-220103

20090104-220243

After validation, Adobe Acrobat tells us our signature is valid:

20090104-220644

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