Tag: Microsoft Platform Crypto Provider

Assume the following scenario:

• A certificate template is configured to use keys based on elliptic curves .
• In addition, the certificate template is configured to use the Microsoft Platform Crypto Provider to protect the private key with the Trusted Platform Module (TPM) of the device.
• The certificate request fails with the following error message:

Error: The requested operation is not supported. 0x80090029 (-2146893783 NTE_NOT_SUPPORTED)

Continue reading "Requesting certificates with elliptic curve based keys fails when using the Microsoft Platform Crypto Provider"

Since Windows NT 4.0, Cryptographic Service Providers (CSP) have been part of the CryptoAPI.

The idea is that an application does not have to worry about the specific implementation of key management, but can leave this to generic operating system interfaces. This also prevents cryptographic keys from being loaded into the working memory in the security context of the user/application used (a fatal security incident based precisely on this problem was the Heartbleed incident ).

For example, it makes no technical difference to the certification authority software how its private key is protected - whether in software or with a hardware security module (HSM), for example. The call of the private key is always identical for the certification authority.

With Windows Vista and the introduction of Cryptography Next Generation (CNG) as a replacement for CryptoAPI, Key Storage Providers (KSP) were introduced.

Continue reading "Basics: Cryptographic Service Provider (CSP) and Key Storage Provider (KSP)"

Since Windows 8, it is possible to protect the private keys of certificates with a Trusted Platform Module (TPM), if one is present . This makes the key non-exportable - even with tools like mimikatz.

However, it is not obvious at first glance that it cannot be guaranteed that a TPM is really used. It is true that no request via the Microsoft Management Console or autoenrollment is possible if the computer does not have a TPM.

However, the configuration in the certificate template is only a default setting for the client. When a certificate is requested, the certification authority will not explicitly check whether a Trusted Platform Module was really used .

To ensure that the private key of a certificate request has really been protected with a Trusted Platform Module, only the TPM Key Attestation remains.

Continue reading "Configuring the Trusted Platform Module (TPM) Key Attestation"

Since Windows 8, it has been possible to protect the private keys of certificates with a Trusted Platform Module (TPM), if one is present. This ensures that the key is truly non-exportable.

The process for setting up a certificate template that uses a Trusted Platform Module is described below.

Continue reading "Configuring a certificate template to use the Microsoft Platform Crypto Provider to enable private key protection by a Trusted Platform Module (TPM)"