Managed I/O - Streams, Readers, and Writers

csharp

C++ CryptoStream Example

Create a new CLR console application project and you might want  to use CryptoStreamSampleCP as the project and solution names.

Add the following code.

//  CryptoStreamSampleCP.cpp : main project file. // < summary> //  This sample is designed to show how to use the composable stream  CryptoStream //  to read and write encrypted data to a file. The sample uses the  DES encryption //  standard to encrypt data. // < /summary> #include "stdafx.h" using namespace System; using namespace System::IO; using namespace System::Security::Cryptography; // < summary> //  The main entry point for the application. // < /summary> [STAThread] int main(array<System::String  ^> ^args) {     // Let's create a  private key that will be used to encrypt and decrypt the data stored  in the file hantu.dat.     array< Byte >^ DESKey = gcnew array< Byte >{200, 5, 78, 232, 9, 6, 0, 4};     array< Byte >^ DESInitializationVector = gcnew array< Byte >{0, 1, 2, 3,  4, 5, 6, 7, 8, 9};      String^ FileName = "C:\\temp\\hantu.dat";      CryptoStream^ MyStreamEncrypter = nullptr;     try      {         // Let's create a  file named hantu.dat in the current C:\Temp directory            FileStream^ MyFileStream = nullptr;         try          {               MyFileStream = gcnew FileStream(FileName, FileMode::Create, FileAccess::Write);               Console::WriteLine("{0}  file created/opened successfully", FileName);          }         catch (Exception^ e)          {             throw gcnew Exception("Failed  to create/open filestream with error: " + e->Message);          }         // Let's create a  Symmetric crypto stream using the DES algorithm to encode all the  bytes written to the file hantu.         try          {              Console::WriteLine("Instantiate  DESCryptoServiceProvider & CryptoStream, encrypting {0}...",  FileName);              DES^ DESAlgorithm = gcnew DESCryptoServiceProvider();              MyStreamEncrypter = gcnew CryptoStream(MyFileStream, DESAlgorithm->CreateEncryptor(DESKey,  DESInitializationVector), CryptoStreamMode::Write);          }         catch (Exception^ e)          {              MyFileStream->Close();             throw gcnew Exception("Failed  to create DES Symmetric CryptoStream with error: " + e->Message);          }         // Let's write 10  bytes to our crypto stream. For simplicity         // we will write an  array of 10 bytes where each byte contains a numeric value 0 - 9.         array< Byte >^ MyByteArray = gcnew array< Byte >(10);                     Console::WriteLine("Writing...");          for (short i = 0; i < MyByteArray->Length; i++)          {              MyByteArray = (Byte)i;              Console::Write("{0},  ", MyByteArray);           }               Console::WriteLine();         try          {                MyStreamEncrypter->Write(MyByteArray, 0, MyByteArray->Length);                Console::WriteLine("Writing  10 bytes to the crypto stream...");          }         catch (Exception^ e)          {             throw gcnew Exception("Write  failed with error: " + e->Message);          }      }     catch (Exception^ e)      {          Console::WriteLine(e->Message);         return 0;      }     finally      {         // Let's close the  crypto stream now that we are finished writing data.          Console::WriteLine("Closing  the encrypter stream...");          MyStreamEncrypter->Close();      }     // Now let's open  the encrypted file Jim.dat and decrypt the contents.      Console::WriteLine();      Console::WriteLine("Opening  the encrypted {0} file and decrypting it...", FileName);      CryptoStream^ MyStreamDecrypter = nullptr;     try      {          FileStream^ MyFileStream = nullptr;         try          {               MyFileStream = gcnew FileStream(FileName, FileMode::Open, FileAccess::Read);               Console::WriteLine("Decrypted  {0} file opened successfully", FileName);          }         catch (Exception^ e)          {             throw gcnew Exception("Failed  to open filestream with error: " + e->Message);          }         try          {              Console::WriteLine("Instantiate  DESCryptoServiceProvider & CryptoStream, decrypting {0}...",  FileName);              DES^ DESAlgorithm = gcnew DESCryptoServiceProvider();              MyStreamDecrypter = gcnew CryptoStream(MyFileStream, DESAlgorithm->CreateDecryptor(DESKey,  DESInitializationVector), CryptoStreamMode::Read);          }         catch (Exception^ e)          {              MyFileStream->Close();             throw gcnew Exception("Failed  to create DES Symmetric CryptoStream with error: " + e->Message);          }         array< Byte >^ MyReadBuffer = gcnew array< Byte >(1);          Console::WriteLine("Reading  the decrypted {0} file content...", FileName);         while (true)          {             int BytesRead;             try              {                  BytesRead = MyStreamDecrypter->Read(MyReadBuffer, 0, MyReadBuffer->Length);              }             catch (Exception^ e)              {                 throw gcnew Exception("Read  failed with error: " + e->Message);              }             if (BytesRead  == 0)              {                  Console::WriteLine("No  more bytes to read...");                 break;              }              Console::WriteLine("Read  byte -> " + MyReadBuffer[0].ToString());          }      }     catch (Exception^ e)      {                Console::WriteLine(e->Message);      }     finally      {         // We are finished  performing IO on the file. We need to close the file to release  operating system resources related to the file.          Console::WriteLine("Closing  the decrypter stream...");          MyStreamDecrypter->Close();      }     return 0; }

Build and run the project. The following is an output example.

csharp

2. 
   
3. #include "stdafx.h"
   
4. 
   
5. using namespace System;
   
6. using namespace System::Text;
   
7. using namespace System::Security::Cryptography;
   
8. using namespace System::IO;
   
9. 
   
10. int main(array<System::String ^> ^args)
    
11. {
    
12.         MemoryStream^ mStream = gcnew MemoryStream();
    
13.         array< Byte >^ DESKey = gcnew array< Byte >{200, 5, 78, 232, 9, 6, 0, 4};
    
14.     array< Byte >^ DESInitializationVector = gcnew array< Byte >{0, 1, 2, 3,  4, 5, 6, 7};
    
15. 
    
16.         String^ unicodeString = L"This unicode string contains two characters with codes outside an 8-bit";
    
17. 
    
18.         UTF8Encoding^ utf8 = gcnew UTF8Encoding;
    
19.         array<Byte>^ data=utf8->GetBytes(unicodeString);
    
20. 
    
21.         DES^ DESAlgorithm =  gcnew DESCryptoServiceProvider();
    
22. 
    
23.         CryptoStream^ cStream = gcnew CryptoStream(mStream,
    
24.                 DESAlgorithm->CreateEncryptor(DESKey, DESInitializationVector),
    
25.                 CryptoStreamMode::Write);
    
26. 
    
27.         cStream->Write(data, 0, data->Length);
    
28.         cStream->FlushFinalBlock();
    
29. 
    
30.         array<Byte>^ ret = mStream->ToArray();
    
31.         Convert^ cvt;
    
32.         String^ retstr=cvt->ToBase64String(ret);
    
33. 
    
34.         cStream->Close();
    
35.         mStream->Close();
    
36. 
    
37.         Console::WriteLine(retstr );
    
38.         System::Console::ReadLine();
    
39.     return 0;
    
40. }
    

<br /> #include "stdafx.h"<br /> <br /> using namespace System;<br /> using namespace System::Text;<br /> using namespace System::Security::Cryptography;<br /> using namespace System::IO;<br /> <br /> int main(array<System::String ^> ^args)<br /> {<br />         MemoryStream^ mStream = gcnew MemoryStream();<br />         array< Byte >^ DESKey = gcnew array< Byte >{200, 5, 78, 232, 9, 6, 0, 4};<br />     array< Byte >^ DESInitializationVector = gcnew array< Byte >{0, 1, 2, 3,  4, 5, 6, 7};<br /> <br />         String^ unicodeString = L"This unicode string contains two characters with codes outside an 8-bit";<br /> <br />         UTF8Encoding^ utf8 = gcnew UTF8Encoding;<br />         array<Byte>^ data=utf8->GetBytes(unicodeString);<br /> <br />         DES^ DESAlgorithm =  gcnew DESCryptoServiceProvider();<br /> <br />         CryptoStream^ cStream = gcnew CryptoStream(mStream, <br />                 DESAlgorithm->CreateEncryptor(DESKey, DESInitializationVector), <br />                 CryptoStreamMode::Write);<br /> <br />         cStream->Write(data, 0, data->Length);<br />         cStream->FlushFinalBlock();<br /> <br />         array<Byte>^ ret = mStream->ToArray();<br />         Convert^ cvt;<br />         String^ retstr=cvt->ToBase64String(ret);<br /> <br />         cStream->Close();<br />         mStream->Close();<br /> <br />         Console::WriteLine(retstr );<br />         System::Console::ReadLine();<br />     return 0;<br /> }<br />

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