Root Certificates vs. Intermediate Certificates: Difference to Know

Introduction

The phrases “root certificates” and “intermediate certificates” will probably come up while you seek an SSL certificate for your website. People could confuse the two words.

The primary distinction between intermediate and root certificates is foremost, their origins. The primary source for the root certificate authority is the trust stores of the major browsers.

However, since they do not have roots in browser trust stores, intermediate certificate authorities or sub-certificate authorities provide an intermediate root. Thus, a trust-party root is where intermediate certificate authority originates.

Was this information excess to take in, then? Don’t stress. We will go into extensive detail about everything in this article.

What is Certificate Hierarchy?

The certificate hierarchy could be obtained, and more information is shown when you save the certificate of a recently found website that you are attempting to connect to.

The first certificate you keep is considered the root certificate; next comes theintermediate CAs, and finally, the final certificate should lead to an authentic CA.

Certificate Chain of Trust Diagram

             ┌─────────────────────────┐
             │     Root CA Certificate │
             │  (Self-signed, trusted) │
             └──────────────┬──────────┘
                            │ signs
                            ▼
             ┌─────────────────────────┐
             │ Intermediate CA Cert #1 │
             └──────────────┬──────────┘
                            │ signs
                            ▼
             ┌─────────────────────────┐
             │ Intermediate CA Cert #2 │
             └──────────────┬──────────┘
                            │ signs
                            ▼
             ┌─────────────────────────┐
             │   Server Certificate    │
             │     (example.com)       │
             └─────────────────────────┘

What is Root Certificate?

A root certificate is a special type of digital certificate that sits at the top of a certificate chain in public key infrastructure (PKI). It is issued by a trusted Certificate Authority (CA) like DigiCert, Sectigo or Globalsign and acts as the ultimate source of trust for secure connections like HTTPS, email encryption, code signing, and more.

Also Read: What Is a Root CA Certificate, and Where Can I Use It?

Importance of Root Certificates

• They are the foundation of internet trust.
• If a root certificate is compromised, all certificates issued under it become untrustworthy, which is why root CA security is extremely strict.

What is Intermediate Certificate?

An intermediate certificate also known as intermediate CA certificate. It is a digital certificate issued by a root Certificate Authority (CA) or another intermediate CA. It sits between the root certificate and the end-entity certificate like a website’s SSL/TLS certificate in the certificate chain. It acts as a middle layer of trust.

Also Read: What Is Intermediate Certificate? How To Download It?

Purpose of the Intermediate Certificate

It protects the entire trust system, the root CA remains trusted.

If an intermediate certificate is compromised, the root CA can revoke just that intermediate certificate.

Root vs Intermediate Certificate Difference

Feature	Root Certificate	Intermediate Certificate
Signed by	Itself (self-signed)	Root CA or another intermediate
Stored in	Trusted root store	Usually delivered by server
Security level	Highest	High but less sensitive
Used to sign	Intermediates (rarely servers)	Server certificates
Purpose	Anchor of trust	Issue end-entity certificates
Lifespan	Long (10–25 yrs)	Shorter (3–7 yrs)

Detailed Explainations and Comparisons

For generating and authenticating digital certificates, the Public Key Infrastructure (PKI) relies on both root certificates and intermediate certificates.

However, there are a few noticeable differences between them.

Brief Outline

The root certificates, saved on all browsers worldwide, are CAs with trustworthy roots.

Intermediate roots are provided by the CAs that issue the intermediate certificates. They are connected to third-party roots but do not utilize browser storage.

Definition

The root certificate in the PKI’s trust hierarchy is a self-signed digital certificate. Building confidence in a digital certificate is achieved by confirming that a trustworthy entity issued it.

A digital certificate that a root certificate can issue is called an intermediate certificate. It acts as a bridge between the end user’s certificate and the root certificate.

Significance in the Trust Chain

The root certificate is considered notable and has a higher value in the chain of trust than an intermediate certificate.

The intermediate certificate has little significance in the trust chain. It acts as an intermediary.

Certificate Issuance

 Root certificates prevent direct SSL certificate issuance by the CA. They employ intermediate certificates to sign the endpoint (SSL) certificates to prevent breaches.

The intermediate certificate serves as a mediator by signing the intermediate certificates, protecting the root certificate, and granting SSL certificates.

Expiration

Root certificates rarely expire and are used for extended periods.

Intermediate certificates frequently have a lower validity period than root certificates.

Also Read: How to Check TLS/SSL Certificate Expiration Date?

Damage in an Emergency

Since the hacker has access to the whole PKI and may undermine trust along the chain hierarchy, manipulating the root certificate might result in catastrophic consequences. Because of this, it’s best to limit its limitations by keeping this certificate offline.

The intermediate certificate loses its use if it has been altered. The sole choice is to eliminate the same and the other intermediates to stop more harm.

Revoke 

Root certificates don’t have to be renewed if a certificate is revoked for whatever reason.

In an emergency, intermediate certifications will be revoked to prevent disaster.

Also Read: How to Fix NET::ERR_CERT_REVOKED_Certificate Error?

Access

The Root Store has access to the root certificate.

The Private Key is used to access the intermediate certificate.

Final thoughts

As you noticed, Root and Intermediate Certificates are significantly different despite having the same purposes.

Understanding these technical details and managing these security certifications is a challenging task. After reading this article, you can understand that regardless of their similarities, these certifications nonetheless differ significantly.

Because Root Certificates are tightly guarded for security, they are never seen by end users and are kept offline. Conversely, the intermediate certificate is maintained on the internet for signatures and the issuing of endpoint and further intermediate certificates.

By now, you should completely grasp what exactly makes a digital certificate secure. You have effectively dealt with the SSL/TLS dilemma by comprehending the difference between root and intermediate certificates. One of the leading causes of the effectiveness and widespread use of SSL certificates is the SSL chain of trust.

Frequently Asked Questions

How can the Root Certificate and Intermediate Certificate be distinguished?

You can distinguish between an intermediate and a root certificate by reviewing the certificate. If the Issued to and issued by fields match, the certificate is a root; otherwise, it is an intermediate. Reputable roots may only be issued by authorized certificate authorities.

How do Intermediate and Root Certificates Appear in the Hierarchy?

The root, intermediate, and server certificates should be in the proper sequence in an SSL certificate chain.

What is the Process for Combining Intermediate and Root CA Certificates?

You only need to aggregate the ASCII data from each PEM certificate into a single file to integrate multiple certificates.

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