X509Certificate Constructor Exception

Question

//cert is an EF Entity and 
//    cert.CertificatePKCS12 is a byte[] with the certificate.

var certificate = new X509Certificate(cert.CertificatePKCS12, \"SomePassw         


        

Answer 1

You need to import a .cer certificate to your local machine keystore. There's no need to import your .p12 cert - instead use the second certyficate issued to your account by Apple. I think it must be a valid pair of certificates (one in filesystem, second in keystore). You'll have to set all 3 flags in dll of course.

Answer 2

On an application running IIS 10, I managed to fix the access denied error by using LocalSystem identity for the app pool with the following code:

new X509Certificate2(certificateBinaryData, "password"
                               , X509KeyStorageFlags.MachineKeySet |
                                 X509KeyStorageFlags.PersistKeySet);

Enabling Load User Profile didn't work for me and while there where many suggestions to do this, they did not indicate that setting for 'Load User Profile' to True only works on user accounts and not:

1. ApplicationPoolIdentity
2. NetworkService

Answer 3

Turns out there's a setting in the IIS Application Pool configuration (Application Pools > Advanced Settings) to load the user profile for the application pool identity user. When set to false, the key containers aren't accessible.

So just set Load User Profile option as True

Answer 4

Use this code:

certificate = new X509Certificate2(System.IO.File.ReadAllBytes(p12File)
                                   , p12FilePassword
                                   , X509KeyStorageFlags.MachineKeySet |
                                     X509KeyStorageFlags.PersistKeySet | 
                                     X509KeyStorageFlags.Exportable);

Answer 5

More than likely, when you are running from Visual Studio/Cassini, it is accessing your user certificate store, even though you're loading it from bytes. Could you please try this and see if it solves your issue:

var certificate = new X509Certificate(
    cert.CertificatePKCS12, "SomePassword", X509KeyStorageFlags.MachineKeySet);

This will cause IIS (which runs as the ASP.NET user which likely doesn't have access to a user store) to use the Machine store.

This page explains the constructor in more detail, and this page explains the X509KeyStorageFlags enumeration.

Edit: Based on the second link from cyphr, it looks like it might be a good idea (if the previous solution doesn't work), to combine some of the FlagsAttribute enumeration values like so:

var certificate = new X509Certificate(
    cert.CertificatePKCS12, "SomePassword",
    X509KeyStorageFlags.MachineKeySet
    | X509KeyStorageFlags.PersistKeySet
    | X509KeyStorageFlags.Exportable);

Additionally, if you have access, you may want to try changing your Application Pool setting to use LocalService (and then restart the AppPool). This may elevate your permissions to an appropriate level if that is the problem.

Finally, you can use File.WriteAllBytes to write out the CertificatePKCS12 contents to a pfx file and see if you can manually import it using the certificate console under MMC (you can delete after successful import; this is just to test). It could be that your data is getting munged, or the password is incorrect.

Answer 6

I had trouble on Windows 2012 Server R2 where my application could not load certificates for a PFX on disk. Things would work fine running my app as admin, and the exception said Access Denied so it had to be a permissions issue. I tried some of the above advice, but I still had the problem. I found that specifying the following flags as the third parameter of the cert constructor did the trick for me:

 X509KeyStorageFlags.UserKeySet | 
 X509KeyStorageFlags.PersistKeySet | 
 X509KeyStorageFlags.Exportable