加密資料

發行項
08/12/2011

對稱加密和非對稱加密是使用不同的處理序 (Process) 來執行。對稱加密在資料流上執行，因此可用於加密大量的資料。非對稱加密是在小量的位元組上執行，因此僅適用於小量資料。

對稱加密

Managed 對稱加密類別會與稱為 CryptoStream 的特殊資料流類別共同使用，這個類別會加密讀取至資料流的資料。 CryptoStream 類別利用 Managed 資料流類別初始化，這種資料流類別會實作 ICryptoTransform 介面的類別 (建立自實作密碼編譯演算法的類別)，並且會描述 CryptoStream 所允許之存取型別的 CryptoStreamMode 列舉。 CryptoStream 類別可利用衍生自 Stream 類別的任何類別 (包括 FileStream、MemoryStream 和 NetworkStream) 來初始化。您可以使用這些類別在各種不同的資料流物件上執行對稱加密。

以下範例說明如何建立 RijndaelManaged 類別的新執行個體，這個執行個體實作 Rijndael 加密演算法，並利用它在 CryptoStream 類別上執行加密。在此範例中，CryptoStream 利用稱為 MyStream 的資料流物件來初始化，這個物件可以是任何的 Managed 資料流型別。傳遞來自 RijndaelManaged 類別的 CreateEncryptor 方法中用來加密的金鑰和 IV。在這種情況下，會使用產生自 RMCrypto 的預設金鑰和 IV。最後，傳遞 CryptoStreamMode.Write，並指定資料流的寫入存取權限。

Dim RMCrypto As New RijndaelManaged()
Dim CryptStream As New CryptoStream(MyStream, RMCrypto.CreateEncryptor(RMCrypto.Key, RMCrypto.IV), CryptoStreamMode.Write)

RijndaelManaged RMCrypto = new RijndaelManaged();
CryptoStream CryptStream = new CryptoStream(MyStream, RMCrypto.CreateEncryptor(), CryptoStreamMode.Write);

這個程式碼執行之後，寫入 CryptoStream 物件的任何資料，都會使用 Rijndael 演算法來加密。

以下範例顯示整個處理序，包括建立資料流、加密資料流、寫入資料流和關閉資料流。這個範例建立使用 CryptoStream 類別和 RijndaelManaged 類別加密的網路資料流。訊息利用 StreamWriter 類別寫入加密資料流。

注意事項
您也可以用此範例寫入檔案。若要執行該作業，請刪除 TcpClient 參考並以 FileStream 取代 NetworkStream。

Imports System
Imports System.IO
Imports System.Security.Cryptography
Imports System.Net.Sockets

Module Module1
Sub Main()
   Try
      'Create a TCP connection to a listening TCP process.
      'Use "localhost" to specify the current computer or
      'replace "localhost" with the IP address of the 
      'listening process. 
      Dim TCP As New TcpClient("localhost", 11000)

      'Create a network stream from the TCP connection. 
      Dim NetStream As NetworkStream = TCP.GetStream()

      'Create a new instance of the RijndaelManaged class
      'and encrypt the stream.
      Dim RMCrypto As New RijndaelManaged()

            Dim Key As Byte() = {&H1, &H2, &H3, &H4, &H5, &H6, &H7, &H8, &H9, &H10, &H11, &H12, &H13, &H14, &H15, &H16}
            Dim IV As Byte() = {&H1, &H2, &H3, &H4, &H5, &H6, &H7, &H8, &H9, &H10, &H11, &H12, &H13, &H14, &H15, &H16}

      'Create a CryptoStream, pass it the NetworkStream, and encrypt 
      'it with the Rijndael class.
      Dim CryptStream As New CryptoStream(NetStream, RMCrypto.CreateEncryptor(Key, IV), CryptoStreamMode.Write)

      'Create a StreamWriter for easy writing to the 
      'network stream.
      Dim SWriter As New StreamWriter(CryptStream)

      'Write to the stream.
      SWriter.WriteLine("Hello World!")

      'Inform the user that the message was written
      'to the stream.
      Console.WriteLine("The message was sent.")

      'Close all the connections.
      SWriter.Close()
      CryptStream.Close()
      NetStream.Close()
      TCP.Close()
   Catch
      'Inform the user that an exception was raised.
      Console.WriteLine("The connection failed.")
   End Try
End Sub
End Module

using System;
using System.IO;
using System.Security.Cryptography;
using System.Net.Sockets;
 
public class main
{
   public static void Main(string[] args)
   {
      try
      {
         //Create a TCP connection to a listening TCP process.
         //Use "localhost" to specify the current computer or
         //replace "localhost" with the IP address of the 
         //listening process.  
         TcpClient TCP = new TcpClient("localhost",11000);
   
         //Create a network stream from the TCP connection. 
         NetworkStream NetStream = TCP.GetStream();

         //Create a new instance of the RijndaelManaged class
         // and encrypt the stream.
         RijndaelManaged RMCrypto = new RijndaelManaged();

         byte[] Key = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16};
         byte[] IV = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16};

         //Create a CryptoStream, pass it the NetworkStream, and encrypt 
         //it with the Rijndael class.
         CryptoStream CryptStream = new CryptoStream(NetStream, 
         RMCrypto.CreateEncryptor(Key, IV),   
         CryptoStreamMode.Write);

         //Create a StreamWriter for easy writing to the 
         //network stream.
         StreamWriter SWriter = new StreamWriter(CryptStream);

         //Write to the stream.
         SWriter.WriteLine("Hello World!");

         //Inform the user that the message was written
         //to the stream.
         Console.WriteLine("The message was sent.");

         //Close all the connections.
         SWriter.Close();
         CryptStream.Close();
         NetStream.Close();
         TCP.Close();
      }
      catch
      {
         //Inform the user that an exception was raised.
         Console.WriteLine("The connection failed.");
      }
   }
}

如果要讓前述範例執行成功，在 TCPCLient 類別中指定的 IP 位址和通訊埠編號上必須有個處理序在接聽。如果接聽處理序存在，這個程式碼將連接到接聽處理序，使用 Rijndael 對稱演算法加密資料流，並將 "Hello World!" 寫入資料流。如果這個程式碼成功，它會對主控台顯示以下內容：

The message was sent.

但是，如果找不到接聽處理序或引發例外狀況，這個程式碼會對主控台顯示以下內容：

The connection failed.

非對稱加密

非對稱演算法通常用來加密小量的資料，例如對稱金鑰和 IV 的加密。通常，個人在執行非對稱加密時會使用由另一方產生的公開金鑰。 RSACryptoServiceProvider 類別是 .NET Framework 針對此目的所提供的類別。

以下範例使用公開金鑰資訊來加密對稱金鑰和 IV。所初始化的兩個位元組陣列代表協力廠商的公開金鑰。 RSAParameters 物件會被初始化為這些值。接下來，RSAParameters 物件 (以及它所代表的公開金鑰) 會利用 RSACryptoServiceProvider.ImportParameters 方法匯入 RSACryptoServiceProvider。最後，加密 RijndaelManaged 類別所建立的私密金鑰和 IV。這個範例要求系統安裝 128 位元的加密。

Imports System
Imports System.Security.Cryptography

Module Module1

    Sub Main()
        'Initialize the byte arrays to the public key information.
      Dim PublicKey As Byte() =  {214, 46, 220, 83, 160, 73, 40, 39, 201, 155, 19,202, 3, 11, 191, 178, 56, 74, 90, 36, 248, 103, 18, 144, 170, 163, 145, 87, 54, 61, 34, 220, 222, 207, 137, 149, 173, 14, 92, 120, 206, 222, 158, 28, 40, 24, 30, 16, 175, 108, 128, 35, 230, 118, 40, 121, 113, 125, 216, 130, 11, 24, 90, 48, 194, 240, 105, 44, 76, 34, 57, 249, 228, 125, 80, 38, 9, 136, 29, 117, 207, 139, 168, 181, 85, 137, 126, 10, 126, 242, 120, 247, 121, 8, 100, 12, 201, 171, 38, 226, 193, 180, 190, 117, 177, 87, 143, 242, 213, 11, 44, 180, 113, 93, 106, 99, 179, 68, 175, 211, 164, 116, 64, 148, 226, 254, 172, 147}

        Dim Exponent As Byte() = {1, 0, 1}

        'Create values to store encrypted symmetric keys.
        Dim EncryptedSymmetricKey() As Byte
        Dim EncryptedSymmetricIV() As Byte

        'Create a new instance of the RSACryptoServiceProvider class.
        Dim RSA As New RSACryptoServiceProvider()

        'Create a new instance of the RSAParameters structure.
        Dim RSAKeyInfo As New RSAParameters()

        'Set RSAKeyInfo to the public key values. 
        RSAKeyInfo.Modulus = PublicKey
        RSAKeyInfo.Exponent = Exponent

        'Import key parameters into RSA.
        RSA.ImportParameters(RSAKeyInfo)

        'Create a new instance of the RijndaelManaged class.
        Dim RM As New RijndaelManaged()

        'Encrypt the symmetric key and IV.
        EncryptedSymmetricKey = RSA.Encrypt(RM.Key, False)
        EncryptedSymmetricIV = RSA.Encrypt(RM.IV, False)
    End Sub

End Module

using System;
using System.Security.Cryptography;

class Class1
{
   static void Main()
   {
      //Initialize the byte arrays to the public key information.
      byte[] PublicKey = {214,46,220,83,160,73,40,39,201,155,19,202,3,11,191,178,56,
            74,90,36,248,103,18,144,170,163,145,87,54,61,34,220,222,
            207,137,149,173,14,92,120,206,222,158,28,40,24,30,16,175,
            108,128,35,230,118,40,121,113,125,216,130,11,24,90,48,194,
            240,105,44,76,34,57,249,228,125,80,38,9,136,29,117,207,139,
            168,181,85,137,126,10,126,242,120,247,121,8,100,12,201,171,
            38,226,193,180,190,117,177,87,143,242,213,11,44,180,113,93,
            106,99,179,68,175,211,164,116,64,148,226,254,172,147};

      byte[] Exponent = {1,0,1};
      
      //Create values to store encrypted symmetric keys.
      byte[] EncryptedSymmetricKey;
      byte[] EncryptedSymmetricIV;

      //Create a new instance of the RSACryptoServiceProvider class.
      RSACryptoServiceProvider RSA = new RSACryptoServiceProvider();

      //Create a new instance of the RSAParameters structure.
      RSAParameters RSAKeyInfo = new RSAParameters();

      //Set RSAKeyInfo to the public key values. 
      RSAKeyInfo.Modulus = PublicKey;
      RSAKeyInfo.Exponent = Exponent;

      //Import key parameters into RSA.
      RSA.ImportParameters(RSAKeyInfo);

      //Create a new instance of the RijndaelManaged class.
      RijndaelManaged RM = new RijndaelManaged();

      //Encrypt the symmetric key and IV.
      EncryptedSymmetricKey = RSA.Encrypt(RM.Key, false);
      EncryptedSymmetricIV = RSA.Encrypt(RM.IV, false);
   }
}

請參閱

概念

產生加密和解密金鑰

解密資料

密碼編譯服務

其他資源

密碼編譯工作

共用方式為

加密資料

對稱加密

非對稱加密

請參閱

概念

其他資源

其他資源