Digital Signature FAQ

What is a Digital Signature?
A digital signature is very much similar to your physical signature; only it is the electronic version of your physical signature. You have to write your physical signature when you are signing documents while you have to electronically insert your digital signature.

Where are digital signatures used?
Digital signatures are used to sign electronic documents. These documents can be in the form of files, e-mails or any other format that is used to share information electronically. They find extensive use in signing PDF files and come pre-embedded in Adobe® Acrobat applications.

How do digital signatures work?
Digital signatures are based on public key infrastructure (PKI). Each digital signature consists of a set of keys – one private and one public. The private key is held by the author or owner of the digital signature while the public key is included in the PKI. When a digital signature is inserted into a document, the author of that document uses his/her private key to sign the document. When the recipient of the document verifies the digital signature on the document, he/she actually draws information included in the PKI regarding the author to verify the identity of the person who has digitally signed the document. Thus digital signatures provide security by identifying and verifying the identity of the author of every document that carries a digital signature. If a document has been modified or tampered with in any way, the digital signature becomes invalid, indicating that the document is not the one that was originally created by the author.

What are certified digital signatures?
Certified digital signatures are highly secure versions of digital signatures. For a digital signature to become certified, the author of that digital signature needs to get his identity verified by a Certification Authority. GeoTrust is one such authority. For certification of a digital signature, the Certification Authority requires the author to file an application and provide identity verification. Only when the identity of the author is thoroughly verified does he get issued a certified digital signature.

What are the benefits of digital signatures?
Digital signatures, including certified ones are of great importance in the communications of enterprises that share data and information electronically. Documents that are digitally signed are very hard to tamper with. With certified digital signatures, it is next to impossible to change information in any manner. Additionally the author of the information or document that is digitally signed does not need to verify his identity to every recipient of the document or information because his/her digital signature does it automatically. Additionally digital signatures also ensure integrity of information and documents because as soon as the information or document gets modified by any person other than the author, the digital signature becomes invalid. Thus digital signatures provide a method of transmitting necessary information securely and reliably.

How can I get a certified digital signature?
For this you will have to apply to a trusted third-party Certification Authority. GeoTrust is one such Certification Authority. Once you file an application, GeoTrust will ask you to submit document relevant to proving your identity and then thoroughly validate all the documents. Once your identity has been established, you will be issued a certified digital signature which you can use on all your documents.

How do I sign documents with a digital signature?
Digital signatures are currently mainly in use in PDF documents. All Adobe® Acrobat applications come with the facility of digitally signing documents pre-embedded. If you apply for and get a certified digital signature, you will be provided with a USB token which you need to install on the USB port of your computer with the related software. Once you do this, you will be able to download your digital signature from the certification authority’s website. Thereafter you can directly start signing all the documents you create using Adobe® Acrobat with this certified digital signature.