A digital certificate is created by public key cryptography and is used for wrapping a public key to a company. It is issued by a certificate authority like VeriSign. The certificate proves that the identity of the company is verified. A user can also check the certificate and its attributes. It is generally used by eCommerce sites to prove their identity. You can see this in the footer of a website.
Classes or levels of digital certificate: A digital certificate is categorized in different classes or levels:
Class 1: In this level a particular email is verified. It is for individuals who want to verify their email address. In this class, identity proof is not verified.
Class 2: This level is for verifying the identity of an individual. Proof of identity is required for applying a class 2 digital certificate.
Class 3: It is generally used for verifying servers and softwares for companies and organizations.