Simple example of using. Net symmetric encryption

  Using  System;
  Using  System. Security. cryptography;
  Using  System. text;
  Using  System. IO;

  ///     <Summary>  
  /// Example of Using symmetric encryption
  ///     </Summary>  
  Class  Class1
{

  Static     Void  Main (  String  [] ARGs)
{
Class1 C  =  New  Class1 ();
C. startdemo ();
}

 Public     Void  Startdemo ()
{
  //  Establish shortric Algorithm  
  Symmetricalgorithm SA  =  Rijndael. Create ();

  //  Key and IV  
  SA. generatekey ();  //  Generate a random (32*8) Key.
 //  SA. generateiv ();  //  Initial vector, which can be used in ECB mode without IV  
  SA. Mode  =  Ciphermode. ECB;  //  Block Processing Mode  
  SA. padding  =  Paddingmode. Zeros;  //  Fill mode of the data block at the end 
  

Console. writeline (  "  The key is:  "  );  /////////  //  
    For  (  Int  I  =  0  ; I  < SA. Key. length; I  ++  )  /////////  //  
  {  /////////  //  
  Console. Write (  "  {0: X2}  "  , SA. Key [I]);  /////////  // 
  }  /////////  //  
  Console. writeline (  "  \ N  "  );  /////////  //  
  

  //  Establish crypto stream  
 Memorystream MS  =     New  Memorystream ();
Cryptostream CS  =     New  Cryptostream (MS, SA. createencryptor (), cryptostreammode. Write );

  //
    String  Plaintext;  //  Original Text  
   Byte  [] Cipherbytes;  //  Encrypted data  
    Byte  [] Finalbytes;  //  Decrypted data  
  
Plaintext  =  "  How are you? This is a line of text.  " ;
  Byte  [] Plainbytes  =  Encoding. utf8.getbytes (plaintext );


Console. writeline (  "  Original Text: \ n {0} \ n  "  , Plaintext );
  //  Display plaint text byte array in hex format  
  Console. writeline (  "  Raw data is: "  );  /////////  //  
    For  (  Int  I  =  0  ; I  <  Plainbytes. length; I  ++  )  ///////// //  
  {  /////////  //  
  Console. Write (  "  {0: X2}  "  , Plainbytes [I]);  /////////  //  
  }  /////////  // 
  Console. writeline (  "  \ N  "  );  /////////  //  
  
  //  Encryption Process  
  CS. Write (plainbytes,  0  , Plainbytes. Length );
CS. Close ();
Cipherbytes =  Ms. toarray ();
Ms. Close ();

  //  Display ciphertext byte array in hex format  
  Console. writeline (  "  The encrypted data is:  "  );  /////////  //  
    For  ( Int  I  =  0  ; I  <  Cipherbytes. length; I  ++  )  /////////  //  
  {  /////////  //  
  Console. Write ( "  {0: X2}  "  , Cipherbytes [I]);  /////////  //  
  }  /////////  //  
  Console. writeline (  "  \ N  "  );  ///////// //  
  

  //  The following describes the encryption process.  
  MS  =  New  Memorystream (cipherbytes );
CS  =  New  Cryptostream (MS, SA. createdecryptor (), cryptostreammode. Read );
Finalbytes  =  New    Byte  [Plainbytes. Length];
CS. Read (finalbytes,  0  , Plainbytes. Length );

Console. writeline (  "  The decrypted data is:  "  );  /////////  //  
    For  (  Int  I =  0  ; I  <  Finalbytes. length; I  ++  )  /////////  //  
  {  /////////  //  
  Console. Write (  "  {0: X2} "  , Finalbytes [I]);  /////////  //  
  }  /////////  //  
  Console. writeline (  "  \ N  "  );  /////////  //  
 
  String  Finaltext  =  Encoding. utf8.getstring (finalbytes );

Console. writeline (  "  The decrypted text is \ n {0} \ n  "  , Finaltext );
Console. writeline (  "  Press any key to continue ......  "  );
Console. Readline ();

}
} 

 

Http://blog.csdn.net/kwanhong/archive/2005/09/22/486783.aspx