About digital signatures
A digital signature, like a conventional handwritten signature, identifies the person signing a
document. Unlike traditional signatures on paper, however, each digital signature stores information
about the person signing a document. Signatures help prevent unwanted changes to a PDF document.
For example, an author may not want a PDF document with company letterhead to be changed after
it's signed. (See
.)
The first signature in a document is called the author signature. When you add the first signature to a
document, you have the option of certifying the document. Certifying a document lets you attest to its
contents and specify the types of changes allowed for the document to remain certified. Changes to
the document are detected in the Signatures tab. Subsequent signatures to the document are called
ordinary signatures.
To sign a document, you must select a digital ID, which contains the signature information that you
can share with other users in a certificate. You can create a self-signed digital ID, or you can obtain a
digital ID from a third-party provider. Using certificates, other users can validate your signatures, and
you should validate the signatures of others. (See
Using digital IDs and certification methods
Note: For the latest information about digital signatures, choose Help > Online Support to open the
Adobe Acrobat support page on the Adobe website, and then search for "digital signatures."
Valid digital signature in a PDF form
Summary of Contents for ACROBAT 3D
Page 1: ......
Page 37: ...What s New in Adobe Acrobat 3D New features ...
Page 95: ...Finding Adobe PDF Files Using Organizer Using the Organizer window ...
Page 184: ...FORMS About Adobe PDF forms Setting Forms preferences ...
Page 241: ...Collecting Data from Submitted Forms Collecting form data by email ...
Page 316: ...SECURITY About security Viewing the security settings of an open Adobe PDF document ...
Page 423: ......
Page 508: ...Optimizing Adobe PDF Documents Using PDF Optimizer ...
Page 571: ...SEARCH AND INDEX About searching Adobe PDF documents ...
Page 602: ...PRINT PRODUCTION About print production in Acrobat ...
Page 729: ...SPECIAL FEATURES About document metadata About JavaScript in Acrobat About Digital Editions ...
Page 738: ...Working with JavaScript Working with JavaScript in Acrobat ...
Page 762: ...ADOBE VERSION CUE About Adobe Version Cue Getting help Key features of Adobe Version Cue ...
Page 809: ...Tutorial Version Cue Getting started with Version Cue ...
Page 821: ...Legal Notices Copyright ...