Question

My server creates a RSACryptoServiceProvider and exports its parameters to a variable (RSAKeyInfo).

Then, the public key is sent to the client, and the client encrypts something with that public key.

Now, I need to be able to decrypt this very data when sent back to the server – hence why RSA is useful in my case.

However, I get a “Bad Data” exception when trying to recreate a RSACryptoServiceProvider with imported parameters from the first RSACryptoServiceProvider created previously.

… Code might be clearer.

Creating the crypto:

class Cryptograph
{
    public Cryptograph()
    {
        this.RSAKeyInfo = new RSACryptoServiceProvider(2048, new CspParameters(1)).ExportParameters(true);
    }
}

Accessing it later for decryption:

byte[] encrypted = ...;

RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
rsa.ImportParameters(this.Cryptograph.RSAKeyInfo);

byte[] decrypted = rsa.Decrypt(encrypted, false);
Console.WriteLine(Utilities.ByteArrayToHexString(decrypted));

I get the “Bad Data” exception at this line:

byte[] decrypted = rsa.Decrypt(encrypted, false);

What am I doing wrong? How can I do it properly?
Thank you 🙂

P.S.: Please don’t send MSDN or obvious Google results links, I’ve read all these pages and still can’t get it to work.

Answer 1

I needed an encryption/decryption that used no padding, and C#.NET doesn’t provide it by default. OpenSSL.NET will do the job, however, I’m stuck while trying to use it. (See this question if you want to help me make it work). 🙁