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RSACryptoServiceProvider Constructor ()

Initializes a new instance of the RSACryptoServiceProvider class using the default key.

Namespace: System.Security.Cryptography
Assembly: mscorlib (in mscorlib.dll)

public RSACryptoServiceProvider ()
public RSACryptoServiceProvider ()
public function RSACryptoServiceProvider ()

Exception typeCondition

CryptographicException

The cryptographic service provider (CSP) cannot be acquired.

If no default key is found, a new key is created.

This constructor creates an Exchange key pair suitable to encrypt session keys so that they can be safely stored and exchanged with other users. The generated key corresponds to a key generated using the AT_KEYEXCHANGE value used in the unmanaged Microsoft Cryptographic API (CAPI).

The following code example uses the RSACryptoServiceProvider class to encrypt a string into an array of bytes and then decrypt the bytes back into a string.

using System;
using System.Security.Cryptography;
using System.Text;

class RSACSPSample
{

	static void Main()
	{
		try
		{
			//Create a UnicodeEncoder to convert between byte array and string.
			UnicodeEncoding ByteConverter = new UnicodeEncoding();

			//Create byte arrays to hold original, encrypted, and decrypted data.
			byte[] dataToEncrypt = ByteConverter.GetBytes("Data to Encrypt");
			byte[] encryptedData;
			byte[] decryptedData;
			
			//Create a new instance of RSACryptoServiceProvider to generate
			//public and private key data.
			RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

			//Pass the data to ENCRYPT, the public key information 
			//(using RSACryptoServiceProvider.ExportParameters(false),
			//and a boolean flag specifying no OAEP padding.
			encryptedData = RSAEncrypt(dataToEncrypt,RSA.ExportParameters(false), false);

			//Pass the data to DECRYPT, the private key information 
			//(using RSACryptoServiceProvider.ExportParameters(true),
			//and a boolean flag specifying no OAEP padding.
			decryptedData = RSADecrypt(encryptedData,RSA.ExportParameters(true), false);

			//Display the decrypted plaintext to the console. 
			Console.WriteLine("Decrypted plaintext: {0}", ByteConverter.GetString(decryptedData));
		}
		catch(ArgumentNullException)
		{
			//Catch this exception in case the encryption did
			//not succeed.
			Console.WriteLine("Encryption failed.");

		}
	}

	static public byte[] RSAEncrypt(byte[] DataToEncrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
	{
		try
		{	
			//Create a new instance of RSACryptoServiceProvider.
			RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

			//Import the RSA Key information. This only needs
			//toinclude the public key information.
			RSA.ImportParameters(RSAKeyInfo);

			//Encrypt the passed byte array and specify OAEP padding.  
			//OAEP padding is only available on Microsoft Windows XP or
			//later.  
			return RSA.Encrypt(DataToEncrypt, DoOAEPPadding);
		}
		//Catch and display a CryptographicException  
		//to the console.
		catch(CryptographicException e)
		{
			Console.WriteLine(e.Message);

			return null;
		}

	}

	static public byte[] RSADecrypt(byte[] DataToDecrypt, RSAParameters RSAKeyInfo,bool DoOAEPPadding)
	{
		try
		{
			//Create a new instance of RSACryptoServiceProvider.
			RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

			//Import the RSA Key information. This needs
			//to include the private key information.
			RSA.ImportParameters(RSAKeyInfo);

			//Decrypt the passed byte array and specify OAEP padding.  
			//OAEP padding is only available on Microsoft Windows XP or
			//later.  
			return RSA.Decrypt(DataToDecrypt, DoOAEPPadding);
		}
		//Catch and display a CryptographicException  
		//to the console.
		catch(CryptographicException e)
		{
			Console.WriteLine(e.ToString());

			return null;
		}

	}
}

import System.*;
import System.Security.Cryptography.*;
import System.Text.*;

class RSACSPSample
{
    public static void main(String[] args)
    {
        try {
            // Create a UnicodeEncoder to convert between byte array and string.
            UnicodeEncoding byteConverter =  new UnicodeEncoding();
            
            // Create byte arrays to hold original, encrypted, 
            // and decrypted data.
            ubyte dataToEncrypt[] = byteConverter.GetBytes("Data to Encrypt");
            ubyte encryptedData[];
            ubyte decryptedData[];
            
            // Create a new instance of RSACryptoServiceProvider to generate
            // public and private key data.
            RSACryptoServiceProvider rsa =  new RSACryptoServiceProvider();
            
            // Pass the data to ENCRYPT, the public key information 
            // (using RSACryptoServiceProvider.ExportParameters(false),
            // and a boolean flag specifying no OAEP padding.
            encryptedData = RSAEncrypt(dataToEncrypt, 
                rsa.ExportParameters(false), false);
            
            // Pass the data to DECRYPT, the private key information 
            //(using RSACryptoServiceProvider.ExportParameters(true),
            // and a boolean flag specifying no OAEP padding.
            decryptedData = RSADecrypt(encryptedData, 
                rsa.ExportParameters(true), false);
            
            // Display the decrypted plaintext to the console. 
            Console.WriteLine("Decrypted plaintext: {0}", 
                byteConverter.GetString(decryptedData));
        }
        catch (ArgumentNullException exp) {
            //Catch this exception in case the encryption did
            //not succeed.
            Console.WriteLine("Encryption failed.");
        }
    } //main 

    public static ubyte[] RSAEncrypt(ubyte dataToEncrypt[], 
        RSAParameters rsaKeyInfo, boolean doOaepPadding) 
    {
        try {
            // Create a new instance of RSACryptoServiceProvider.
            RSACryptoServiceProvider rsa =  new RSACryptoServiceProvider();
            
            // Import the rsa Key information. This only needs
            // toinclude the public key information.
            rsa.ImportParameters(rsaKeyInfo);
            
            // Encrypt the passed byte array and specify OAEP padding.  
            // OAEP padding is only available on Microsoft Windows XP or
            // later.  
            return rsa.Encrypt(dataToEncrypt, doOaepPadding) ;
        }
        // Catch and display a CryptographicException  
        // to the console.
        catch (CryptographicException e) {
            Console.WriteLine(e.get_Message());
            return null ;
        }
    } //RSAEncrypt

    public static ubyte[] RSADecrypt(ubyte dataToDecrypt[], 
        RSAParameters rsaKeyInfo, boolean doOaepPadding) 
    {
        try {
            // Create a new instance of RSACryptoServiceProvider.
            RSACryptoServiceProvider rsa =  new RSACryptoServiceProvider();
            
            // Import the rsa Key information. This needs
            // to include the private key information.
            rsa.ImportParameters(rsaKeyInfo);
            
            // Decrypt the passed byte array and specify OAEP padding.  
            // OAEP padding is only available on Microsoft Windows XP or
            // later.  
            return rsa.Decrypt(dataToDecrypt, doOaepPadding) ;
        }
        // Catch and display a CryptographicException  
        // to the console.
        catch (CryptographicException e) {
            Console.WriteLine(e.ToString());
            return null ;
        }
    } //RSADecrypt
} //RSACSPSample

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

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