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

Question

I am staring at this for quite a while and thanks to the MSDN documentation I cannot really figure out what\'s going. Basically I am loading a PFX file from the disc into a

Answer 1

For others that end up here through Google, but don't use any X509Certificate2, if you call ToXmlString on RSACryptoServiceProvider but you've only loaded a public key, you will get this message as well. The fix is this (note the last line):

var rsaAlg = new RSACryptoServiceProvider();

rsaAlg.ImportParameters(rsaParameters);

var xml = rsaAlg.ToXmlString(!rsaAlg.PublicOnly);