But first, what is a digital signature and a digital signature certificate?

A digital signature is derived from a mathematical technique that is used to validate the authenticity and integrity of any kind of digital information such as message, digital document or even a software. Being the digital equivalent of a handwritten signature or the age-old stamped seal, a digital signature, by its nature, provides security of a much greater magnitude.
With inherent security traits such as encryption, it offers solutions to tampering, identity theft, and data fraud in digital communications. A digital signature also contains the added assurances of evidence of where, how and by whom an electronic document or activity was created and/or managed.

Digital signatures are increasingly being considered as legally binding in the same way as traditional document signatures. Today, various countries publish electronically versions of the budget, public and private laws, and congressional bills with digital signatures.

Digital signature technology works on the principle of public key cryptography. The distinguishing technique used in public key cryptography is the use of asymmetric key algorithms, where a key used by one party to perform encryption is not the same as the key used by another in decryption. Each user has a pair of cryptographic keys – a public encryption key and a private decryption key.

Therefore, digital signatures are used by generating two keys that are mathematically linked - one private and one public. Digital signatures work because public key cryptography depends on two mutually authenticating cryptographic keys. The individual who is creating the digital signature uses their own private key to encrypt signature-related data; the only way to decrypt that data is with the signer's public key. This is how digital signatures are authenticated.

The next step - a digital signature certificate.

A digital signature certificate is the electronic document that contains the digital a signature, identifying the issuing authority so as to allow the user. It binds together a public key with an identity so as to be used to verify that a public key belongs to a particular person or entity.

Almost all of our email communication involves digital sign-offs. The modern email programs support the use of digital signatures and digital signature certificates. This makes for a simplified flow of communication by ensuring validation of both digitally-signed incoming and outgoing messages. This way, you can be assured of authentic proof, data integrity and confirmation of activities made online.