[Tugindia] Digitally signing pdf

[Mayuresh]

How can one digitally sign a pdf generated with pdflatex?

Some options I explored till now are:

Acrobat reader which is freely available can attach a digital signature to
a pdf that contains "signature field". Is there any way to create such
add signature field to a pdf when creating it?

There are iText APIs that can sign pdfs, though are there any ready tools
using these APIs that can achieve this?

Libreoffice /  Openoffice has signing feature but only for their native
odf file format. When you export as PDF, signature is not included.

Mayuresh.