Private Certificate Authority 101: From Setup to Management

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Introduction
Security has become a primary focus in today’s world, which is dominated by computers and technology. Businesses are always on a quest to find better ways how secure their information and messages.
Another important component in the field of ‘cyber security’ is the understanding and management of certification. These are generally in the form of certificates that are provided by Public Certification Authorities, abbreviated as CAs. Still, in some cases, an organization might find that a private CA is preferable.
In this article, you will learn what a private CA is, the advantages that come with using it, and how you can get started with establishing one.
What is a Private CA?
A Private CA, as the name suggests, is a system that is designed within an organization for issuing certificates and managing the authentication scheme for the organization. While public CAs work with countless people signing up for their certificates, a private CA is set up and managed solely by the organization that establishes it.
Also Read: What is Private PKI vs. Public PKI? Uses and Key Differences
Key Points about Private CAs:

Internal Use: They award it only for its use in each organization or company since it is not a recognized qualification.
Full Control: Regarding the operational authority, the CA reporting organization is fully in charge of the CA’s operations and policies.
Limited Trust: Instead of generating certificates that are automatically accepted by the external system, the program needs to be developed.
Cost-Effective: They can also be more cost-effective when used internally within a large organization.
Customizable: This means that there are flexibility aspects that are inherent within policies and the various certificate types concerning the needs of organizations.

Also Read: What Is Public Key Encryption? Public vs. Private Key Encryption
Advantages of a Private Certificate Authority
Setting up a private CA offers several advantages for organizations:
Cost-Effective:
A private CA is beneficial for organizations requiring several certificates because, compared to purchasing from a public CA, it will cost less. This is even more accurate with large enterprises that tend to have a considerable number of internal systems and devices.
Enhanced Control:
In the case of private CA, the organization has complete control over the certificate from the beginning to the end. This is regarding issuance, renewal, and revocation actions that may be taken on the licenses. Since it is internal, you are in a position to regulate it and even adjust the policies if necessary, without having to consult other entities.
Customization:
When it comes to certificate policies, there is a level of flexibility that allows someone to manage them as per his or her wants. This comprises configuring its validity periods, specifying certain fields within the certificate, and issuing certificates for purposes unlikely to be provided by public CAs.
Improved Security:
When you have the certificates stored in your organization, you can limit the exposure of your organization’s data to external vulnerabilities. You have direct managerial control of all the certificates, and this means that it is easier to implement more secure measures on the certificates.
Flexibility:
Private CAs make it possible to issue certificates for the testing and development environments. This can help in a big way to reduce the development cycles as well as internal testing of secure systems.
Faster Operations:
By using a private CA, you can generate and renew the certificates much faster than by using a public CA. This can be very important in big organizations that require the fast implementation of new systems.
Enhanced Privacy:
A private CA implies that you do not have to issue the internal network information to the outside world. This is handy in preserving the secrecy of your network topology, together with internal host names.
Compliance Support:
One can also obtain a certain certification related to data protection and privacy by using a private CA. It enables you to get more control over certificate-specific information processing and storage.
Offline Capabilities:
Private CAs can work in fully offline modes, which can be necessary in high-security environments, in particular, air-gapped networks.
Also Read: What Is Certificate Authority? Role & PKI Trust Hierarchies
Uses and Applications of Private CAs
Private CAs have a wide range of applications within an organization:
Intranet Security:
Strengthen the protection of internal websites and applications with SSL/TLS certificates. That way, internal communications are also encrypted, which is always important.
Email Signing and Encryption:
Bring out S/MIME certificates for the usage of secure Email communications for digital signatures as well as for encrypting internal Emails.
Code Signing:
Liberate internally developed software by signing it with a Code Signing Certificate so that everyone can discern its soundness and source. This is particularly useful for organizations that have in-house development of software and distribute their products within their circle.
VPN Authentication:
Making sure that remote connections to their networks can only be granted by the certificate for VPN connections. This presents a safer form of identification other than having to use passwords and account details.
IoT Device Authentication:
Provide for the management of certificates for the Internet of Things devices within the organization. This is important for protecting the increasingly popular connected devices in companies and corporations.
DevOps and Testing:
Meaning certificates for development and testing environments should be generated easily and rapidly. This enables developers to work on multiple features simultaneously while security is tested in the later stages.
Document Signing:
It is necessary to create provisions that will allow digital signatures in internal documents so that they will be authentic and have a proper level of protection.
Server-to-Server Communication:
Internal server isolation makes it possible for all the traffic between the internal servers to be secure and authenticated.
Client Authentication:
Issue certificates for user authentication on internal systems, providing a strong, certificate-based alternative to passwords.
Mobile Device Management:
Manage certificates for company-issued mobile devices, ensuring secure access to corporate resources from these devices.
Wi-Fi Authentication:
Use certificates for authenticating devices to corporate Wi-Fi networks, enhancing security compared to shared passwords.
Database Encryption:
Issue certificates for encrypting sensitive databases, ensuring data-at-rest protection.
How to Set Up Your Private Certificate Authority?
Setting up a private CA involves several steps. Here’s a detailed guide:

Choose Your Platform: Several options are available for setting up a private CA:
OpenSSL: An open-source, command-line tool that’s flexible and widely used.
Microsoft Active Directory Certificate Services: A Windows-based solution, ideal for organizations already using Active Directory.
EJBCA: An open-source, enterprise-grade CA software.

Prepare Your Environment:

Use a dedicated, secure machine for your CA. This should be a computer that’s not used for any other purpose.
Ensure the machine is not connected to the internet to minimize security risks.
Install OpenSSL on your chosen operating system. Most Linux distributions come with OpenSSL pre-installed.

Create the Root CA:

Generate a strong private key: This command creates a 4096-bit RSA key encrypted with AES-256.

openssl genrsa -aes256 -out rootCA.key 4096

Create a root certificate: This creates a self-signed root certificate valid for 1024 days (about 3 years).

openssl req -x509 -new -nodes -key rootCA.key -sha256 -days 1024 -out rootCA.pem
Using an intermediate CA adds an extra layer of security.

Generate the intermediate key:

openssl genrsa -aes256 -out intermediateCA.key 4096

Create a certificate signing request (CSR):

openssl req -new -key intermediateCA.key -out intermediateCA.csr

Sign the intermediate certificate with the root CA:

openssl x509 -req -in intermediateCA.csr -CA rootCA.pem -CAkey rootCA.key -CAcreateserial -out intermediateCA.pem -days 730 -sha256
This creates an intermediate certificate valid for 730 days (2 years).
Create a Certificate Revocation List (CRL):
A CRL is crucial for managing revoked certificates.
openssl ca -gencrl -out crl.pem
Set Up a Certificate Policy:
Create a comprehensive document outlining:

Who can request certificates
What types of certificates will you issue
How long will certificates be valid
How to handle certificate revocation
Procedures for key management and storage
Auditing and logging requirements

Implement Security Measures:

Store the root CA offline in a secure location
Use hardware security modules (HSMs) for key storage
Implement strict access controls to CA systems
Regularly audit your CA operations
Use strong passwords and multi-factor authentication for CA Access

Issue Certificates:
This creates a certificate valid for 365 days (1 year).

Install these certificates on all devices and systems in your organization
Set up automatic updates for certificate changes
Provide clear instructions for users on how to install and trust these certificates

Implement a Certificate Management System:

Use a system to track issued certificates
Set up alerts for expiring certificates
Automate renewal processes where possible
Implement a workflow for certificate requests and approvals

Train Your Team:

Educate IT staff on CA operations and security best practices
Train end-users on certificate usage and security practices
Conduct regular refresher courses to keep everyone updated on policies and procedures

Regular Maintenance:

Perform security audits of your CA infrastructure regularly
Update software and systems to patch any vulnerabilities
Review and update your certificate policy as needed
Conduct periodic key rotation for added security

Plan for Disaster Recovery:

Create secure backups of your CA
Develop a plan for CA compromise scenarios
Regularly test your disaster recovery procedures

Monitor and Log CA Activities:

Implement comprehensive logging of all CA activities
Regularly review logs for any suspicious activities
Use security information and event management (SIEM) tools for real-time monitoring

Integrate with Existing Systems:

Connect your CA with directory services like LDAP for user management
Integrate with your organization’s identity and access management systems
Set up automated certificate deployment to servers and devices where possible

Conclusion
Setting up and managing a private CA can be complex and requires ongoing attention to security and operational details. For a comprehensive, user-friendly PKI solution that simplifies certificate management while maintaining robust security, consider Certera’s advanced PKI platform, including Private CA.
Our solution offers seamless integration with existing systems, automated certificate lifecycle management, and expert support to ensure your private CA meets all your organization’s needs and security requirements.
Frequently Asked Questions
Is a private CA suitable for all organizations?
It is most preferable for large organizations that have several departments or structures within the organization. Businesses with lower volumes may prefer public CAs due to their flexibility and lower setup costs.
How often should I update my private CA’s root certificate?
Root certificates generated are usually long-lived and could be between 10 to 20 years. Nevertheless, an annual review of the CA setting is recommended, and root certificates should be reviewed and/or updated every 5-10 years or in case of a shift in cryptographic standards.
Can certificates from a private CA be used on public websites?
Although it is feasible, MKA does not recommend it. Any website facing the public should use certificates from publicly trusted CAs to accommodate a large number of clients and gain their trust.
A root CA is the trust anchor and signs intermediate CA certificates. Intermediate CAs issue end-entity certificates, providing an additional layer of security and operational flexibility. Checkout the Difference here.
How can I ensure the security of my private CA?
Make sure to use good, secure algorithms, enhance the ways of storing keys (you need to use hardware security modules), employ proper access rights, conduct regular reviews of the CA activities, and isolate the root CA from the network most of the time.

Janki Mehta
Janki Mehta is a passionate Cyber-Security Enthusiast who keenly monitors the latest developments in the Web/Cyber Security industry. She puts her knowledge into practice and helps web users by arming them with the necessary security measures to stay safe in the digital world.

*** This is a Security Bloggers Network syndicated blog from EncryptedFence by Certera – Web & Cyber Security Blog authored by Janki Mehta. Read the original post at: https://certera.com/blog/private-certificate-authority-101-from-setup-to-management/

About Author

AndyC

Andy Curtis is an award-winning security consultant, researcher and public speaker. He has been working in the computer security industry since the early 1990s, having been employed by state and federal government, leading healthcare and banking providers across three continents. He has given talks about computer security for some of the world’s largest companies, worked with law enforcement agencies on investigations into hacking groups, and is a regular voice on TV and radio explaining IT security threats.

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