RSACryptoServiceProvider 類別

使用由密碼編譯服務供應者 (CSP) 提供之 RSA 演算法的實作，執行非對稱加密和解密。這個類別無法被繼承。

(宣告)

Public NotInheritable Class RSACryptoServiceProvider
 Inherits RSA
 Implements ICspAsymmetricAlgorithm

(使用方式)

Dim instance As RSACryptoServiceProvider

下列程式碼範例會使用 RSACryptoServiceProvider 類別，將字串加密成位元組陣列，然後再將位元組解密回字串。

Imports System
Imports System.Security.Cryptography
Imports System.Text

_

Class RSACSPSample


 Shared Sub Main()
     Try
         'Create a UnicodeEncoder to convert between byte array and string.
         Dim ByteConverter As New UnicodeEncoding()

         'Create byte arrays to hold original, encrypted, and decrypted data.
         Dim dataToEncrypt As Byte() = ByteConverter.GetBytes("Data to Encrypt")
         Dim encryptedData() As Byte
         Dim decryptedData() As Byte

         'Create a new instance of RSACryptoServiceProvider to generate
         'public and private key data.
         Dim RSA As 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 e As ArgumentNullException
         'Catch this exception in case the encryption did
         'not succeed.
         Console.WriteLine("Encryption failed.")
     End Try
 End Sub


 Public Shared Function RSAEncrypt(ByVal DataToEncrypt() As Byte, ByVal RSAKeyInfo As RSAParameters, ByVal DoOAEPPadding As Boolean) As Byte()
     Try
         'Create a new instance of RSACryptoServiceProvider.
         Dim RSA As 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 e As CryptographicException
         Console.WriteLine(e.Message)

         Return Nothing
     End Try
 End Function


 Public Shared Function RSADecrypt(ByVal DataToDecrypt() As Byte, ByVal RSAKeyInfo As RSAParameters, ByVal DoOAEPPadding As Boolean) As Byte()
     Try
         'Create a new instance of RSACryptoServiceProvider.
         Dim RSA As 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 e As CryptographicException
         Console.WriteLine(e.ToString())

下列程式碼範例會使用 RSACryptoServiceProvider，將建立的金鑰資訊匯出到 RSAParameters 物件。

Try

 'Create a new RSACryptoServiceProvider object. 
 Dim RSA As New RSACryptoServiceProvider()

 'Export the key information to an RSAParameters object.
 'Pass false to export the public key information or pass
 'true to export public and private key information.
 Dim RSAParams As RSAParameters = RSA.ExportParameters(False)


Catch e As CryptographicException
 'Catch this exception in case the encryption did
 'not succeed.
 Console.WriteLine(e.Message)
End Try
         Return Nothing
     End Try
 End Function
End Class 

內容來源：微軟的MSDN