What is KSP Library? How to Configure DigiCert ® KeyLocker KSP Library?

Every developer, at some point, faces that “uh-oh” moment when they need to sign code, authenticate drivers, or secure executables and suddenly encounter strange terms like KSP, HSM, or CNG.

Relax. You don’t need to be a PKI expert to make it work.

In this guide, we’ll break down exactly what the DigiCert® KeyLocker KSP library is, why it matters, and how you can configure it.

What Exactly Is the KSP Library?

KSP stands for Key Storage Provider. Think of it as a secure vault built into Windows that holds your cryptographic keys, those secret pieces of data that power encryption and digital signatures.

Now, here’s where DigiCert KeyLocker KSP comes into play.

What is DigiCert KeyLocker KSP?

The DigiCert® KeyLocker KSP is a Microsoft CNG (Cryptography Next Generation) based client tool that lets you sign software without ever moving your actual files or keys around.

Instead of sending your entire file to a signing service, the KSP uses a hash-based signing process, meaning it signs a fingerprint (hash) of your file, not the file itself. That keeps your intellectual property safe and your signing workflow fast.

Why Should You Care About KSP?

If you build or release software especially for Windows, you need to sign it.

Unsigned executables or installers often trigger scary Unknown Publisher Warnings that kill user trust instantly.

Storing private keys locally (on your laptop or build server) is risky. One breach, one leak, and your entire software reputation could go down in flames.

That’s why DigiCert’s KeyLocker KSP exists to give you cloud-level key protection while still integrating seamlessly with Windows signing tools.

What Microsoft Tools Work with DigiCert® KeyLocker KSP?

It will merge with all your preferred Windows signing software. KeyLocker KSP may be directly used with:

• SignTool – the utility to use when signing executables and scripts.
• Mage – is used to sign ClickOnce application manifests and deployment manifests.
• NuGet – to sign NuGet package files in the .NET environments.

All these can be done with your personal keys locked in the hardware-based KeyLocker platform of DigiCert. It is the way that developers today secure their software supply chain end-to-end.

What Can the KSP Sign?

Almost everything you can think of in the Microsoft ecosystem, including:

• Executables (.exe)
• Installers (.msi)
• Application files
• Drivers
• Scripts (.ps1, .vbs)
• System images

If it’s something you’d normally sign to prove authenticity or prevent tampering, KSP can do that.

Recommended: How to Sign Executables Using DigiCert KeyLocker CloudHSM?

Steps to Configure KeyLocker KSP Library

Step 1: Download the DigiCert KeyLocker KSP Library

If you’ve already installed the Windows Client Installer, congratulations, the KSP is already downloaded and registered for you.

But if not, here’s what to do:

• Log in to your DigiCert KeyLocker portal.
• In the KeyLocker menu, go to Resources → Client Tool Repository.
• Find the latest KSP version that matches your OS.
• Click the download icon.

Once downloaded, install it just like any other Windows application.

Step 2: Register the KSP Library

Now let’s get it recognised by Windows. Open Command Prompt (with admin privileges), then run:

smctl windows ksp register

This command registers the DigiCert KeyLocker KSP with Windows CryptoAPI.

Step 3: Check the KSP Installation

To make sure it is all configured properly, execute this command:

certutil.exe -csp “DigiCert Software Trust Manager KSP” -key -user

This confirms that your system is capable of verifying successfully with the DigiCert KeyLocker service. In case it does not crash, congrats! Your KSP is up, and you can sign safely.

Step 4: Synchronise Certificates

Now, for your signing tools to actually access the private keys (stored safely in KeyLocker), you’ll need to sync your certificates to the local store.

Don’t worry, this doesn’t move your private key. It stays secure in DigiCert’s cloud. You’re just syncing the certificate metadata.

Run this command:

smctl windows certsync

Then, open Certificate Manager to check:

certmgr.msc

Make sure you’re viewing the correct user account. Each Windows account has its own certificate store. If you can see your certificate listed there, you’re good to go.

Step 5: Start Signing

Now comes the exciting part. Actually signing your files.

For example, to sign an executable:

signtool sign /n "Your Certificate Name" /fd SHA256 /tr http://timestamp.digicert.com /td SHA256 yourapp.exe

Your signing request goes securely through the KSP library to DigiCert KeyLocker, signs the hash, and returns the signature.

Common Troubleshooting Tips

Problem	Fix
KSP not detected	Re-run smctl windows ksp register and restart
No certificates visible	Run smctl windows certsync again, then check certmgr.msc
Signing fails with permission error	Run your signing tool as Administrator
Using the wrong store	Make sure you’re in the correct Windows user certificate store

Why Developers and Enterprises Love KeyLocker KSP

• Zero Key Exposure – Your private keys never leave DigiCert’s secure environment.
• Seamless Integration – Works natively with Microsoft’s trusted signing tools.
• Access Controls – Define who can sign what, and when.
• Full Visibility – Get complete audit trails of all signing operations.
• Scalability – Perfect for individual developers and large enterprises.

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