Saves a private key string to a PKCS-8 EncryptedPrivateKeyInfo file
public static int SaveEncPrivateKey( string outputFile, string privateKey, int iterationCount, string password, Rsa.PbeOptions pbeOption, Rsa.Format format )
Public Shared Function SaveEncPrivateKey ( _ outputFile As String, _ privateKey As String, _ iterationCount As Integer, _ password As String, _ pbeOption As Rsa.PbeOptions, _ format As Rsa.Format _ ) As Integer
If successful, the return value is zero; otherwise it returns an error code