What is digital certificate and digital signature?

Let us begin by learning about the digital certificate.

Digital Certificate

It is basically a certificate issued digitally, issued to verify a user's authenticity i.e., verifying the user sending a message is who he or she claims to be, and also to provide the receiver with the means to encode a reply.

Whoever wants to or an individual who wants to send encrypted messages applies for a digital certificate from a Certificate Authority (CA).

Need of digital certificate

The digital certificate allows entities to share their public key in an authenticated way. They are used in initializing and establishing secure SSL (Secure Sockets Layer) connections between web browsers and web servers.

Given below is a diagram of digital certificate

Digital signature

A digital signature or a digital code which is generated and authenticated by public key encryption is a mathematical scheme verifying the authenticity of digital messages or documents.

A valid digital signature with prerequisites in place ensures a recipient believes the message was indeed created and sent by a known sender thus authenticating him/her, and the message was not modified in transit thus meeting the integrity condition.

The digital signature is based on RSA and public key cryptography which depends on two mutually authenticating cryptographic keys. The creator and the sender creating the digital signature uses his/her own private key to encrypt signature-related data and to decrypt that data the signer's public key is used which is the only key to decrypt it.

Purpose of digital signature

It is attached to an electronically transmitted document verifying its contents and the sender's identity authenticating him. It is used for software distribution, financial transactions, and contract management software.

Given below is the diagram for digital signature −