CryptographicException "Key not valid for use in specified state." while trying to export RSAParameters of a X509 private key

Solution 1:

I believe that the issue may be that the key is not marked as exportable. There is another constructor for X509Certificate2 that takes an X509KeyStorageFlags enum. Try replacing the line:

X509Certificate2 x = new X509Certificate2(@"C:\temp\certs\1\test.pfx", "test");

With this:

X509Certificate2 x = new X509Certificate2(@"C:\temp\certs\1\test.pfx", "test", X509KeyStorageFlags.Exportable);

Solution 2:

For the issue I encountered a code change was not an option as the same library was installed and working elsewhere.

Iridium's answer lead me to look making the key exportable and I was able to this as part of the MMC Certificate Import Wizard.

Hope this helps someone else. Thanks heaps

Solution 3:

I've met some similar issue, and X509KeyStorageFlags.Exportable solved my problem.

Solution 4:

I'm not exactly an expert in these things, but I did a quick google, and found this:

http://social.msdn.microsoft.com/Forums/en/clr/thread/4e3ada0a-bcaf-4c67-bdef-a6b15f5bfdce

"if you have more than 245 bytes in your byte array that you pass to your RSACryptoServiceProvider.Encrypt(byte[] rgb, bool fOAEP) method then it will throw an exception."