Encryption certificates must contain Data Encipherment or Key Encipherment

Question

After upgrading to Windows Management Framework 5.0, I have started to receive the following exception when sourcing a DSC configuration.

ConvertTo-MOFInstance : System.ArgumentException error processing property 'Password' OF TYPE 'MSFT_Credential': Certificate
'---HIDDEN-CERTIFICATE-THUMPRINT-VALUE---' cannot be used for encryption. Encryption certificates must contain the Data Encipherment or Key
Encipherment key usage, and include the Document Encryption Enhanced Key Usage (1.3.6.1.4.1.311.80.1).
At C:\Windows\system32\WindowsPowerShell\v1.0\Modules\PSDesiredStateConfiguration\PSDesiredStateConfiguration.psm1:303 char:13
+             ConvertTo-MOFInstance MSFT_Credential $newValue
+             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : InvalidOperation: (:) [Write-Error], InvalidOperationException

The certificate being is used on each node is a self-signed certificate that is generated using the following certificate request.

[NewRequest]
Subject = CN=[computer-name-here].dsc
KeyLength = 2048
MachineKeySet = true
RequestType = Cert
KeySpec = AT_KEYEXCHANGE

This request file is then fed to the certreq command line utility to generate the cert and load it into cert:\LocalMachine\My certificate store.

I have tried adding the following to my certificate request file, based on the documentation for the certreq tool, but I still am getting the same failure.

KeyUsage = 0x30
[Strings]
szOID_ENHANCED_KEY_USAGE = "1.3.6.1.4.1.311.80.1"

Setting KeyUsage to 0x30 enables both key encipherment and data encipherment. However I am cannot seem to find details about the enhanced key usage in the generated certificate. Perhaps I'm setting this value incorrectly in the request.

Please help.

Answer 1

I found the blog post PowerShell V5 New Feature: Protect/Unprotect-CmsMessage by Keith Hill, which doesn't directly relate to this issue but it does show how to define a certificate request file that contains the Document Encryption key usage.

I now generate a self signed certificate using the following request inf:

[Version]
Signature = "$Windows NT$"

[Strings]
szOID_ENHANCED_KEY_USAGE = "2.5.29.37"
szOID_DOCUMENT_ENCRYPTION = "1.3.6.1.4.1.311.80.1"

[NewRequest]
Subject = "CN=test.dsc"
KeyLength = 2048
MachineKeySet = true
RequestType = Cert
KeySpec = AT_KEYEXCHANGE
KeyUsage = CERT_KEY_ENCIPHERMENT_KEY_USAGE

[Extensions]
%szOID_ENHANCED_KEY_USAGE% = "{text}%szOID_DOCUMENT_ENCRYPTION%"