A digital signature is a mathematical technique used to validate the authenticity and integrity of a message, software or digital document.

It can be understood as a handwritten signature, but it offers far more security, a digital signature is intended to solve problem of tampering and impersonation in digital communications. It also confirms the identity and status of an electronic document.

Most modern email programs support digital signatures and digital certificates. It helps them sign any outgoing document, which adds authenticity to the documents. It had also helped in reducing paper and ink work in most organizations.