Client Authentication SSL Certificates After 2026: A Secure Alternative for Intranet & Private Applications

Public Certificate Authorities (CAs) are changing how SSL/TLS certificates work.

As per recent CA/Browser Forum decisions, public CAs will stop issuing certificates that support client authentication starting June 15, 2026. While this change improves security for public websites, it creates a serious challenge for enterprises, intranet applications, and closed user groups that rely on client authentication or mutual TLS (mTLS).

This is where SecureNT Intranet SSL becomes highly relevant.

What Is Client Authentication in SSL/TLS?

Client authentication (also called mutual TLS or mTLS) is a security mechanism where:

• The server verifies the client certificate
• The client verifies the server certificate
• Only trusted users, devices, or applications can connect

This approach is commonly used in:

• Intranet applications
• Enterprise software
• Partner portals
• Supplier and vendor systems
• Machine-to-machine (M2M) communication
• API security

Many existing software products depend on client authentication and cannot simply switch to password-based access.

Why Public CAs Are Stopping Client Authentication

Public CAs are designed primarily for public-facing websites accessed through browsers.

Because client authentication certificates introduce risks in the public ecosystem, the CA/Browser Forum has decided to restrict public CAs from issuing SSL certificates with client authentication capability after 2026.

The result:

• Public SSL certificates → Server authentication only
• Client authentication → No longer supported by public CAs

This leaves a gap for private and internal applications.

The Problem for Enterprises and Software Vendors

If your application requires client authentication:

• You may need to redesign security
• Existing deployments may stop working
• Public CA certificates will no longer be suitable
• Security teams must look for private SSL alternatives

We are already seeing this shift.

Recently, an existing customer asked:

“Do you provide SSL certificates for a closed group of users with client authentication?”

The answer was yes — SecureNT Intranet SSL.

SecureNT Intranet SSL: Built for Client Authentication

SecureNT Intranet SSL/TLS is designed specifically for private networks and controlled user groups.

Unlike public CA certificates, SecureNT supports:

• Client Authentication (mTLS)
• Server Authentication
• Closed user groups
• Internal, partner, and intranet applications
• Custom trust models

SecureNT acts as a private Certificate Authority tailored for enterprise use — exactly what client authentication requires.

Long-Term SSL Certificates for Intranet Applications

Public SSL certificates are limited to short validity periods.
Intranet systems often require long-term stability.

SecureNT Intranet SSL certificates are available for:

• 1 year
• 3 years
• 5 years
• 10 years

This reduces operational overhead and avoids unnecessary certificate churn.

Who Should Use SecureNT Intranet SSL?

SecureNT is ideal if:

• Your software requires client authentication SSL
• Your users belong to a closed or trusted group
• Your application runs on intranet, VPN, or private networks
• You are impacted by public CA policy changes
• You need mutual TLS (mTLS) beyond browser trust

Preparing for the Post-2026 SSL Landscape

The removal of client authentication from public CAs is not a temporary change — it is a permanent shift.

Organizations that rely on mTLS must act early.

SecureNT Intranet SSL allows you to:

• Continue using client authentication
• Maintain existing architectures
• Stay compliant and secure
• Avoid rushed redesigns