What is a Digital Certificate?

What is a Digital Certificate?

A digital certificate is a tool much like a password. In Public Key Infrastructure digital certificates confirm the identity of network traffic. A digital certificate proves that you are who you say you are when operating within a network.
Digital certificates ensure encryption of end to end communication. For instance, preventing malicious users from accessing the information sent through your packets. Certificates also provide non-repudiation services. Thus ensuring a user cannot deny they signed a certificate.


How do Certificates work?

A digital signature ensures the authenticity of a document, email, or other data. This relies on key pairs. Decryption requires a private key pair.
To receive linked keys, you need a digital certificate. The certificate allows you to access both the public and private keys in question.

The role of the Digital Certificate Authority

The Certificate Authority or CA acts as a trusted third-party. Then the CA verifies the identity of those generating key pairs. Those applying for a certificate submit a Certificate Signing Request or CSR. The CSR is a file with the information included in the certificate. This will be the domain name, organisation and other information.

X.509 Certificates

A trusted Public Key Infrastructure requires a certificate in the X.509 V3 format. These certificates specialise in the inclusion of data known as ‘extensions’. Browsers might choose to ignore invalid, non-critical extensions, but must process critical extensions.

Digital Certificate Validation Process

Cryptographic signatures make use of a private key to sign certificates, providing non-repudiation. Browsers will act by validating a certification path for X.509 certificates. Using the root certificate, a browser will confirm the certificate path

Certificate Revocation

There are two types of confirmation for certificate revocation and identification.  CRL’s (Certificate Revocation Lists). A Certificate Revocation List provides a time-stamped list of revoked certificates. However, in most cases the OSCP (Online Certificate Status Protocol) has replaced CRL’s.
OSCP is an online protocol designed to check the validity of a certificate via an OCSP client. In most cases the client is a browser. The browser will allow a client to query the issuing CA via the OSCP server. The server will respond telling the client if the certificate is valid and why.


Cogito Group is an award-winning cybersecurity company specialising in authentication, cloud security, identity management and data protection. Cogito Group protect the authentication methods used to access information through the use of Identity and other security technologies.