Digitally signing and certifying PDF Documents

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PDF is the defacto file type to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems. Aspose.PDF Cloud provides a number of operations that work seamlessly with your existing PDF documents, allowing you to convert to and from PDF formats, extract document information and manipulate your PDF documents on cloud storage of your choice.

Aspose.PDF Cloud allows users to sign and/or certify their PDF documents before distributing downstream. This would give your customers an added sense of security, that their PDF files have not been intentionally or unintentionally modified since they were authored.

How is signing different from certifying?

When signing a PDF document using a signature, you basically confirm its contents “as is”. Consequently, any other changes made afterward invalidate the signature and thus, you would know if the document was altered.

Whereas, certifying a document first allows you to specify the changes that a user can make to the document without invalidating the certification.

How do you know your document is signed?

When a document has a valid certification, a blue ribbon in a blue bar will show above the document in the viewer, like this:


In this case, the document originated from the United States Government Printing Office.

What signing algorithms does Aspose.PDF Cloud support?

As of now, we support the following standards

NameDescription
PKCS1Represents signature object regarding PKCS#1 standard. RSA encryption algorithm and SHA-1 digest method are used for signing.
PKCS7Represents the PKCS#7 object that conforms to the PKCS#7 specification in Internet RFC 2315, PKCS #7: Cryptographic Message Syntax, Version 1.5. The SHA1 digest of the document’s byte range is encapsulated in the PKCS#7 SignedData field.
PKCS7DetachedRepresents the PKCS#7 object that conform to the PKCS#7 specification in Internet RFC 2315, PKCS #7: Cryptographic Message Syntax, Version 1.5. The original signed message digest over the document’s byte range is incorporated as the normal PKCS#7 SignedData field. No data shall is encapsulated in the PKCS#7 SignedData field.

How to add a signature with Adobe Acrobat?

In Adobe Reader click on Get Documents Signed
On the left hand, a poup will appear. Click on Place Signature under the Fill and Sign Tools Section.

Drag a Rectangular portion over the document where you want to add your signature stamp.


Enter the password to your signing authority and the PDF will be saved with the stamp.

How to add a signature with Aspose.PDF Cloud?

Here we are going to sign a PDF page using Aspose.PDF Cloud.

Want to know if the document has been signed? Lets try the same operation again. Rather then the 200 response we get the following result

Have any Question

Feel free to drop us a comment below sharing your thoughts about Aspose.PDF Cloud REST API. Or let’s know if you have any suggestions or if you need any particular features which you expect our REST API to have.

Try It Out

And if you’ve not already had a chance to try our REST API, simply start a free trial today. All you need is to sign up with the aspose.cloud. Once you’ve signed up, you’re ready to try the powerful file processing features offered by aspose.cloud.