Windows service 2025 AD CS - I am not able to create PQ CA based on ML-DSA

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Windows service 2025 AD CS - I am not able to create PQ CA based on ML-DSA

Tadeáš Janků 0

Hello, I'd like to create a new CA based on PQ algorithm ML-DSA on the Windows Service 2025 server. I am using the version which you can see on the screen below. According to my information it should be sufficient enough to use the ML-DSA algorithm.

However, when I navigate through the steps in the AD CS configuration I am not able to choose the ML-DSA key from the options. What's also strange is that when I use the command in the CMD it suddenly works. Why can't I create the PQ CA from the GUI?

Thank you for your help

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Answer 1

Allan Solomon Mejia 10,225

Hello @Tadeáš Janků

Your Windows Server 2025 build is new enough, but there is an important distinction: ML-DSA support in AD CS requires Windows Server 2025 with the May 2026 security update (KB5087539) or later, and Microsoft’s documented ML-DSA CA deployment procedure isn't simply selecting ML-DSA from the traditional Server Manager AD CS configuration wizard.

Microsoft now supports ML-DSA-44, ML-DSA-65, and ML-DSA-87 for newly deployed Root, Subordinate, Enterprise, and Standalone CAs. It also requires CNG Key Storage Providers; legacy CSPs aren't supported.

So the fact that the command-line configuration works while the Server Manager wizard doesn't expose ML-DSA doesn't necessarily mean your OS lacks PQC support. Follow Microsoft's dedicated “Configure a certification authority to use ML-DSA” procedure rather than the conventional AD CS wizard.

Also note that Microsoft explicitly states that an ML-DSA CA must be newly installed; you can't migrate an existing CA in place to ML-DSA.

References:

Microsoft - Configure a CA to use ML-DSA

Microsoft - ML-DSA support in AD CS

So don't troubleshoot the missing Server Manager selection as a cryptographic-provider failure yet. If Microsoft's documented ML-DSA command-line procedure succeeds, the underlying platform support is present; the GUI simply may not expose the new PQC configuration path.

Help make this community better for everyone: if this answer resolved your issue, please accept it or upvote it. If not, share more details in a comment so we can continue the discussion and find the right solution.

Tadeáš Janků 0 Reputation points

2026-09-03T11:59:47.0233333+00:00

Hello @Allan Solomon Mejia ,

I did a reainstalation and it suddenly shows the ML-DSA key as an option. I am not sure why it didn't work but thank you for your help.

But I'd like to ask you one more question. As you can see in the picture, I can create ECDSA and RSA key within an nShield HSM, but this isn't an option for ML-DSA key. Why is it? And is it possible to have a PQ key inside a HSM? Thanky you for your answer.

Kind regards, Tadeáš Janků
Allan Solomon Mejia 10,225 Reputation points

2026-09-03T13:22:59.3266667+00:00

Hello @Tadeáš Janků

Glad the reinstall resolved the first issue.

Regarding the HSM: yes, ML-DSA keys can potentially be hardware-backed, but only if the HSM vendor's CNG/KSP implementation supports ML-DSA. Windows/AD CS cannot make an HSM store an ML-DSA key simply because Windows itself supports the algorithm. Microsoft specifically requires a CNG Key Storage Provider for ML-DSA.

In your screenshot, the important clue is that ML-DSA is currently offered only as:

ML-DSA:44#Microsoft Software Key Storage Provider

ML-DSA:65#Microsoft Software Key Storage Provider

ML-DSA:87#Microsoft Software Key Storage Provider

While RSA/ECDSA are also being advertised by the nShield provider. That indicates the currently installed nShield CNG provider isn't advertising ML-DSA to AD CS.

Interestingly, Entrust's newer nShield Security World CNG documentation (v13.9.5) now lists ML-DSA among the supported signature interfaces. So hardware-backed ML-DSA appears possible with an appropriate/current nShield software, firmware, HSM model, and configuration, but verify your exact combination with Entrust before changing the CA.

Microsoft's current AD CS setup documentation itself uses the Microsoft Software Key Storage Provider for ML-DSA CA keys.

Therefore, check the installed nShield Security World/CNG version and ask Entrust whether your specific HSM and firmware support ML-DSA through the Windows CNG KSP for AD CS. If supported, the corresponding nShield ML-DSA provider should need to be correctly installed/registered and exposed to Windows; otherwise, the Microsoft Software KSP will remain the available option.

Reference: ML-DSA support in AD CS

Do not move a production CA to ML-DSA on the HSM until Entrust confirms that the exact AD CS + CNG configuration is supported.

Help make this community better for everyone: if this answer resolved your issue, please accept it or upvote it. If not, share more details in a comment so we can continue the discussion and find the right solution.
Tadeáš Janků 0 Reputation points

2026-09-03T15:36:15.06+00:00

Hello @Allan Solomon Mejia

Thank you for your assist. I'll contact Entrust with the issue and ask them for the confirmation of the configuration.

There is a chance that I'll ask you for help once again, if I don't solve it with Entrust, so please don't close the issue. Thanks.

Best regards, Tadeáš Janků

Answer 2

Tadeáš Janků 0

Hello, I did a reainstalation and it suddenly shows the ML-DSA key as an option. I am not sure why it didn't work but thank you for your help.

But I'd like to ask you one more question. As you can see in the picture, I can create ECDSA and RSA key within an nShield HSM, but this isn't an option for ML-DSA key. Why is it? And is it possible to have a PQ key inside a HSM? Thanky you for your answer.

Kind regards, Tadeáš Janků

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