What is a Certificate Authority (CA)? All You Need to Know

By Tibor Moes / Updated: June 2023

What is a Certificate Authority (CA)? All You Need to Know<br />

What is a Certificate Authority (CA)?

Imagine yourself shopping online, entering your payment information, and hitting the “confirm” button, only to find out later that the website was a cleverly designed scam. How can you be sure that the websites you visit are legitimate and secure? This is where certificate authorities (CVs) come into play. CAs are vital organizations that help maintain a secure digital ecosystem and ensure that your online transactions are protected from fraudsters and hackers. Get ready to dive into the fascinating world of CAs and digital certificates, and learn how they play a crucial role in keeping the internet secure.


  • A Certificate Authority (CA) is a trusted entity that issues digital certificates to verify identities on the internet.

  • The CA validates the identity of the certificate requester (individual or organization) before issuing a certificate.

  • Digital certificates issued by a CA are critical for secure communication and transactions online, establishing trust in digital identities.

Don’t become a victim of cybercrime. Protect your devices with the best antivirus software and your privacy with the best VPN service.

Understanding Certificate Authorities (CAs)

Have you ever wondered how you can trust a website with your personal and financial information? The answer lies in the expertise of Certificate Authorities (CAs). These trusted organizations play a vital role in online security by verifying websites and other entities, ensuring you know who you’re communicating with online. CAs provide certificate authentication, which helps websites build trust with browsers and users, bringing identity into the equation.

Digital certificates, issued by CAs, contain crucial information such as the entity’s name, contact details, organization, domain name, public key, and the certificate’s issue and expiry date. They also include the name of the issuing CA and its digital signature, which serves as proof that the certificate has not been tampered with and can be trusted.

In a nutshell, CAs are essential for online security and help build trust between website owners and their customers, preventing attacks such as man-in-the-middle schemes.

The Purpose of a CA

The primary function of a Certificate Authority (CA) is to verify the identities of entities and issue digital certificates that vouch for their authenticity. These certificates act as digital passports, allowing secure communication between users and websites. When you access a website with a valid digital certificate, you can be confident that you’re interacting with a legitimate entity and not an imposter.

CAs issue different types of digital certificates, such as Domain Validation (DV), Organization Validation (OV), and Extended Validation (EV), each catering to specific use cases and validation levels. These certificates play a crucial role in establishing the Public Key Infrastructure (PKI) and the chain of trust, which are essential components of secure online communication.

Trustworthiness and Reputation

In the digital world, the reputation of a Certificate Authority (CA) is of utmost importance. The trustworthiness and reputation of CAs help us recognize who we’re communicating with online and determine if we can trust them with our data. In essence, the more reputable and trustworthy a CA, the more secure and reliable the digital certificates they issue.

CAs are responsible for verifying the authenticity of websites, domains, and organizations, playing a critical role in building trust in the digital ecosystem. As a result, a CA’s reputation is not only essential for the validity of the certificates they issue, but also for the overall security and reliability of the internet.

The Process of Issuing a Digital Certificate

Obtaining a digital certificate from a CA involves a series of steps, starting with identity verification. The CA must confirm the identity of the requester, ensuring that they are who they claim to be. This process is crucial for maintaining a secure digital environment, as it guarantees the legitimacy of the entity requesting the certificate.

Once the requester’s identity is verified, they must submit a Certificate Signing Request (CSR) to the CA. The CSR contains the requester’s public key and other identifying details. After the CSR is submitted and reviewed, the CA generates the public-private key pair and delivers the signed digital certificate to the requester.

This certificate can then be used to establish secure connections and encrypted communications with users.

Identity Verification

Before issuing a digital certificate, a CA must verify the identity and legitimacy of the entity requesting it. This identity verification process can involve various methods such as knowledge-based authentication, two-factor authentication, credit bureau-based authentication, database methods, online verification, and biometric verification.

The type of digital certificate issued depends on the level of validation performed by the CA. Domain Validation (DV) certificates verify domain ownership, while Organization Validation (OV) and Extended Validation (EV) certificates authenticate the organization’s identity and its legal, physical, and operational existence.

This thorough verification process helps create trust between website owners and their customers, ensuring that the site’s ownership and legitimacy are verified and secure.

Certificate Signing Request (CSR)

A Certificate Signing Request (CSR) is a vital step in obtaining a digital certificate from a CA. The requester provides their public key and other identifying details to the CA in the CSR. This information is used by the CA to validate the requester’s identity and generate the public-private key pair required for secure communication.

Submitting a CSR signifies that the requester has completed the identity verification process and is now ready to receive their digital certificate. Once the CA receives the CSR, they review it and, if everything is in order, issue the signed digital certificate.

Certificate Delivery

Upon successful completion of the identity verification and CSR submission, the CA delivers the signed digital certificate to the requester. The delivery process varies depending on the type of SSL certificate and the specific CA, but it usually takes a few days for the SSL certificate to be activated after purchase.

With the signed digital certificate in hand, the requester can now establish secure connections and encrypted communications with users, ensuring that their data is safe from prying eyes and potential threats. The digital certificate serves as a badge of trust, vouching for the legitimacy and security of the website or service it represents.

Types of Certificates Issued by CAs

CAs issue a variety of digital certificates to cater to different use cases and levels of validation. These certificates enable encrypted connections and secure communication between users and websites or services. The three main types of certificates issued by CAs are Domain Validation (DV), Organization Validation (OV), and Extended Validation (EV).

Each type of certificate serves a distinct purpose and offers varying levels of validation. DV certificates verify domain ownership, OV certificates authenticate organizations’ identities, and EV certificates provide the highest level of validation, ensuring that the organization’s legal, physical, and operational existence is verified.

Let’s delve deeper into each type of certificate and their specific use cases.

Domain Validation (DV) Certificates

Domain Validation (DV) certificates are the most basic type of digital certificate issued by a CA. They verify that the domain name in the certificate is the same as the domain name of the website. DV certificates are typically issued quickly and at a lower cost compared to other types of certificates, making them a popular choice for website owners who simply need to establish a secure connection.

Although DV certificates provide a basic level of security, they do not authenticate the organization’s identity, and thus may not be suitable for websites that handle sensitive user data or financial transactions. In such cases, a higher level of validation, such as OV or EV certificates, is recommended.

Organization Validation (OV) Certificates

Organization Validation (OV) certificates go a step further than DV certificates by not only verifying the domain name but also confirming the identity of the organization that owns the domain. These certificates require the CA to validate the organization’s business registration information, ensuring that users can trust the legitimacy of the website they are visiting.

OV certificates are ideal for organizations that handle sensitive information, such as personal data or financial transactions. They provide an extra layer of trust by authenticating the organization’s identity, reducing the risk of users falling victim to fraudulent websites or phishing attacks.

Extended Validation (EV) Certificates

Extended Validation (EV) certificates represent the highest level of validation and security among digital certificates issued by CAs. These certificates require a more thorough identity check than other certificate types, verifying the organization’s legal entity, as well as its legal, physical, and operational existence. The stringent validation process associated with EV certificates ensures that users can trust the website they are visiting, and that their data is protected from malicious threats.

EV certificates are particularly well-suited for websites handling sensitive user information or financial transactions, such as e-commerce platforms or online banking services. By displaying the organization’s name in the URL bar, EV certificates provide users with a visual cue that the website is secure and trustworthy, reducing the risk of falling victim to phishing attacks or other online scams.

Public Key Infrastructure (PKI) and the Chain of Trust

Public Key Infrastructure (PKI) is a system of encryption and authentication that uses public keys and digital certificates to protect digital communications. At the heart of PKI lies the chain of trust, a hierarchical model that includes root certificates, intermediate certificates, and SSL certificates. CAs play a key role in PKI, issuing digital certificates and managing certificate revocation through mechanisms such as Certificate Revocation Lists (CRLs) and the Online Certificate Status Protocol (OCSP).

The chain of trust is essential for creating secure connections and encrypted communications between users and websites. By establishing trust between all parties involved in an electronic exchange, PKI ensures the authenticity and security of digital communications, keeping your data safe from potential threats.

Root Certificates

Root certificates are the foundation of trust within the PKI, acting as the ultimate authority for all certificates issued by a CA. These public key certificates identify a root certificate authority and verify that the software or website owner is who they claim to be. Root certificates are critical to the authenticity and security of digital communications, ensuring that only valid certificates are used for authentication and encryption.

CAs issue root certificates after verifying the identity of the requester, creating a Certificate Signing Request (CSR), and delivering the certificate. Root certificates can issue various types of digital certificates, such as DV, OV, and EV certificates, depending on the level of validation required.

Intermediate Certificates

Intermediate certificates are subordinate certificates issued by a trusted root certificate authority and given to other CAs to issue SSL/TLS certificates. These certificates act as a bridge between the root certificate and the end-entity certificate, creating a chain of trust that links the end-entity certificate back to the root certificate.

Intermediate certificates play a crucial role in ensuring the trustworthiness and security of end-entity certificates. By establishing a chain of trust, intermediate certificates validate the authenticity of the end-entity certificate, guaranteeing that users can trust the website or service it represents. Without intermediate certificates, the chain of trust would be incomplete, and the end-entity certificate would not be considered reliable.

Certificate Revocation and Management

Certificate revocation and management are essential aspects of maintaining a secure digital environment. Certificates may be revoked for a variety of reasons, such as being compromised, issued incorrectly, or no longer required by the requester. To keep track of revoked certificates and prevent their use for authentication or encryption, CAs utilize mechanisms such as Certificate Revocation Lists (CRLs) and the Online Certificate Status Protocol (OCSP).

Proper certificate management ensures that only valid and trustworthy certificates are used in digital communications, protecting users from potential threats and malicious actors. By staying up-to-date with revoked certificates and implementing effective management practices, CAs help maintain a secure and reliable digital ecosystem.

Certificate Revocation List (CRL)

A Certificate Revocation List (CRL) is a list of digital certificates that have been revoked by the issuing CA before their actual expiration date. CRLs serve as a powerful tool for keeping track of revoked certificates, ensuring that they cannot be used for authentication or encryption.

CRLs play a pivotal role in internet security, as they help prevent the validation of certificates that should not be trusted. By regularly updating and distributing CRLs, CAs can effectively alert users to potentially fraudulent websites or malicious copies of legitimate sites, safeguarding their online interactions.

Online Certificate Status Protocol (OCSP)

The Online Certificate Status Protocol (OCSP) is a real-time alternative to CRLs, allowing users to check the status of a digital certificate instantly. OCSP sends a request to the CA that issued the certificate, which then responds with a signed message indicating the certificate’s current status. This real-time verification process provides a more secure and reliable method of validating certificates than relying solely on CRLs.

OCSP is an essential component of a robust certificate management system, ensuring that users are protected from potential threats and malicious websites. By providing real-time certificate status information, OCSP enables users to make informed decisions about the legitimacy and trustworthiness of the websites they visit, enhancing overall internet security.

Public vs. Private Certificate Authorities

Public and private Certificate Authorities (CAs) serve distinct roles and use cases in the digital ecosystem. Public CAs are trusted automatically by web browsers and operating systems, issuing certificates to anyone who pays the required fee. In contrast, private CAs are utilized internally within an organization, issuing certificates for internal use and limiting their certificates to specific entities.

Both public and private CAs play essential roles in establishing trust and maintaining security in the digital world. Public. Public. CAs build trust across the broader internet community, while private CAs help secure internal networks and authenticate users within an organization.

Understanding the differences and use cases of public and private CAs can help you make informed decisions about which type of CA is most suitable for your needs.

Public CAs

Public Certificate Authorities (CAs) issue certificates that are trusted by web browsers, operating systems, and other internet users. They provide a service that verifies the requesting organization’s identity and charges a fee for the issuance of digital certificates. Public CAs are responsible for issuing root and intermediate certificates, creating the chain of trust, and managing certificate revocation through mechanisms such as CRLs and OCSP.

Public CAs play a critical role in establishing trust in the digital ecosystem, as they ensure that only valid and secure certificates are used for authentication and encryption. By issuing publicly trusted certificates, public CAs help website owners protect their users’ data and maintain a secure online environment.

Private CAs

Private Certificate Authorities (CAs) operate within an organization’s internal network, issuing digital certificates for internal use rather than for public trust. These certificates are used to secure internal networks, authenticate users, and encrypt data, ensuring a high level of security within the organization.

Private CAs can be cost-effective and efficient for organizations that require a high level of control over their internal security infrastructure. By managing their own certificates, organizations can tailor their security measures to meet their unique needs and ensure that their internal communications and data are protected from potential threats.


In conclusion, Certificate Authorities (CAs) play an indispensable role in maintaining a secure and trustworthy digital ecosystem. By issuing digital certificates, managing certificate revocation, and overseeing the chain of trust, CAs help protect users from potential threats and ensure that their data remains safe and secure.

Understanding the various types of digital certificates, the role of CAs in Public Key Infrastructure (PKI), and the differences between public and private CAs is crucial for navigating the complex world of online security. As we continue to rely more heavily on digital communication and transactions, the importance of CAs in safeguarding our online experiences grows ever more vital. Stay vigilant, trust the experts, and keep your digital world secure!

How to stay safe online:

  • Practice Strong Password Hygiene: Use a unique and complex password for each account. A password manager can help generate and store them. In addition, enable two-factor authentication (2FA) whenever available.
  • Invest in Your Safety: Buying the best antivirus for Windows 11 is key for your online security. A high-quality antivirus like Norton, McAfee, or Bitdefender will safeguard your PC from various online threats, including malware, ransomware, and spyware.
  • Be Wary of Phishing Attempts: Be cautious when receiving suspicious communications that ask for personal information. Legitimate businesses will never ask for sensitive details via email or text. Before clicking on any links, ensure the sender's authenticity.
  • Stay Informed. We cover a wide range of cybersecurity topics on our blog. And there are several credible sources offering threat reports and recommendations, such as NIST, CISA, FBI, ENISA, Symantec, Verizon, Cisco, Crowdstrike, and many more.

Happy surfing!

Frequently Asked Questions

Below are the most frequently asked questions.

What does a certificate authority CA do?

A certificate authority (CA) is an organization that verifies and authenticates digital identities, issuing digital certificates that serve to establish secure connections between different systems. CA’s also issue and manage public encryption keys which allow for data and communication to remain secure.

What is a certificate authority?

A certificate authority (CA) is an entity that requires proof of identity from the individual requesting a certificate and generates a digitally signed identification certificate. This certificate can be used to verify the identity of the requestor in a secure manner.

It plays a key role in providing trust and security to digital communications and transactions.

What is an example of a certificate authority?

A Certificate Authority (CA) is an entity which issues digital certificates used to verify the identity of a user or device and enable secure connections over the internet. Popular examples include Comodo, GeoTrust, and Symantec.

These organizations help ensure secure online transactions and communications by verifying the authenticity of websites, users, and other entities.

Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor is a Dutch engineer and entrepreneur. He has tested security software since 2014.

Over the years, he has tested most of the best antivirus software for Windows, Mac, Android, and iOS, as well as many VPN providers.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

This website is hosted on a Digital Ocean server via Cloudways and is built with DIVI on WordPress.

You can find him on LinkedIn or contact him here.

Security Software

Best Antivirus for Windows 11
Best Antivirus for Mac
Best Antivirus for Android
Best Antivirus for iOS
Best VPN for Windows 11

Cybersecurity articles

Ad Blocker
AES Encryption
Antivirus – How Does it Work
Antivirus – What is it
Antivirus vs Firewall
Antivirus vs Internet Security
API Security
Application Security
Authentication Examples
Biometrics Examples
Certificate Authority (CA)
Cloud Security
Cryptography Examples
Cryptography Types
Cyber Hygiene
Cyber Insurance
Cyber Resilience
Cyber Safety
Cyber Security
Cyber Security Examples
Cyber Security Types
Cyber Threat Intelligence
Dark Web Monitoring
Data Encryption
Data Integrity Examples
Data Loss Prevention (DLP)
Data Privacy
Data Security
Disaster Recovery (DR)
Do Android Phones Need Antivirus
Do Chromebooks Need Antivirus
Do iPhones Need Antivirus
Do Macs Need Antivirus
Does Linux Need Antivirus
Does Windows 10 Need Antivirus
Does Windows 11 Need Antivirus
Email Encryption
Encryption Key
Endpoint Security
False Positives
File Encryption
Firewall – What Does it Do
Firewall Examples
Firewall Types
Heuristic Analysis
How to Clean and Speed up Your PC
HTTPS Examples
Incident Response
Information Security (InfoSec)
Information Security Types
Internet Security
Internet Security Software
Intrusion Detection System (IDS)
Intrusion Detection System Examples
Intrusion Detection System Types
Intrusion Prevention System (IPS)
Intrusion Prevention System Examples
Intrusion Prevention System Types
IoT security
Multi-Factor Authentication (MFA)
Multi-Factor Authentication Examples
Network Security
Network Security Key
Network Security Types
Next-Generation Firewall (NGFW)
Obfuscated Server
Onion over VPN
Parental Controls
Password Examples
Password Manager
Patch Management
Penetration Testing (Pen Testing)
Penetration Testing Types
Proxy Server vs VPN
Public Key Infrastructure (PKI)
Quantum Cryptography
Red Team
Sandbox Environment
Secure Sockets Layer (SSL)
Security Audit
Security Operations Center (SOC)
Security Policy
Security Policy Examples
Software Patching
Software Security
SSL Certificate
SSL Certificate Types
SSL Handshake
Threat Hunting
Threat Intelligence
Threat Modeling
Threat Modeling Examples
Two-Factor Authentication (2FA)
Two-Factor Authentication Examples
Virtual Keyboard
Virtual Private Network (VPN)
VPN Examples
VPN Kill Switch
VPN Protocol
VPN Split Tunneling
VPN Tunnel
VPN Types
Vulnerability Scan
Web Application Firewall (WAF)
White Hat Hacker
Windows Defender
Wireguard vs OpenVPN
Zero Trust Architecture