Windows 7 Import PKCS#12 works, export seems to succeed, but no private key is present in pfx

Why is the Private Key Not Exported in Windows 7?​

1. Changes in Key Storage Mechanisms: Windows operating systems handle key storage and encryption differently. Windows 7 may have more stringent security measures that prevent the automatic export of private keys, especially when they are considered sensitive.
2. Encryption Algorithms: Windows versions might use different encryption algorithms or key algorithms by default, leading to variations in how keys are handled during import and export operations.

   Programmatic Solution to Export Private Key:​

   To address the issue programmatically and ensure the private key is exported with the certificate, you might need to manipulate the key during the export process. Here's an approach you could consider:
3. Accessing Key with Extended Properties: As you noted, importing with extended properties seems to work. This may be related to specific properties or settings associated with the key during import.
4. Using a Key Storage Provider: You could explore using a cryptographic service provider (CSP) or a key storage provider (KSP) in your Visual Studio 2008 project to handle key management operations more granularly.
5. Custom Key Export Logic: Implement custom logic in your application to extract and export the private key explicitly during the export process, ensuring it is included in the resulting PFX file.
6. Check Compatibility: Ensure that the methods and APIs used for key operations in your Visual Studio 2008 project are compatible with the security mechanisms and key management protocols of Windows 7.

   Additional Considerations:​

   • Security Implications: Keep in mind that handling private keys programmatically requires attention to security best practices to prevent unauthorized access.
   • Consult Documentation: Refer to Windows SDK documentation, particularly the sections related to key management, cryptography, and Windows version-specific behavior for further insights. By customizing your export process and ensuring compatibility with Windows 7's key management mechanisms, you can potentially resolve the issue of private key export in your PFX files programmatically. If you require further assistance or clarification on specific technical details, feel free to provide more information for a more targeted resolution.