Answer by Akram Shahda for .NET Private Key Rsa Encryption

I guess that is what are you looking for:

    // Import ASymmetric RSA Key from a system file.    public static RSAParameters ImportRSAKey(String fileName)    {        // Create a stream to a the specified system file.        Stream fileStream = new FileStream(fileName, FileMode.Open, FileAccess.Read);        // Extract/Deserialize the key from the file.        IFormatter soapFormatter = new SoapFormatter();                    RSAParameters rsaParameter =            (RSAParameters) soapFormatter.Deserialize(fileStream);        // Close the file stream.        fileStream.Close();        return rsaParameter;    }

To generate a new key, you can use RSACryptoServiceProvider.ExportParameters method.

Refer to the following:

RSAParameters Structure