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SymmetricAlgorithm.CreateEncryptor Method

Updated: December 2010

Creates a symmetric encryptor object with the current Key property and initialization vector (IV).

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)
public virtual ICryptoTransform CreateEncryptor()

Return Value

Type: System.Security.Cryptography.ICryptoTransform
A symmetric encryptor object.

If the current Key property is null, the GenerateKey method is called to create a new random Key. If the current IV property is null, the GenerateIV method is called to create a new random IV.

Use the CreateDecryptor overload with the same signature to decrypt the result of this method.

The following example encrypts a string by using the transform object that is returned from the CreateEncryptor method.

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

class EncryptorExample
{
     private static string quote =
         "Things may come to those who wait, but only the " +
         "things left by those who hustle. -- Abraham Lincoln";

     public static void Main()
     {
         AesCryptoServiceProvider aesCSP = new AesCryptoServiceProvider();

         aesCSP.GenerateKey();
         aesCSP.GenerateIV();
         byte[] encQuote = EncryptString(aesCSP, quote);

         Console.WriteLine("Encrypted Quote:\n");
         Console.WriteLine(Convert.ToBase64String(encQuote));

         Console.WriteLine("\nDecrypted Quote:\n");
         Console.WriteLine(DecryptBytes(aesCSP, encQuote));
     }

     public static byte[] EncryptString(SymmetricAlgorithm symAlg, string inString)
     {
         byte[] inBlock = UnicodeEncoding.Unicode.GetBytes(inString);
         ICryptoTransform xfrm = symAlg.CreateEncryptor();
         byte[] outBlock = xfrm.TransformFinalBlock(inBlock, 0, inBlock.Length);

         return outBlock;
     }

     public static string DecryptBytes(SymmetricAlgorithm symAlg, byte[] inBytes)
     {
         ICryptoTransform xfrm = symAlg.CreateDecryptor();
         byte[] outBlock = xfrm.TransformFinalBlock(inBytes, 0, inBytes.Length);

         return UnicodeEncoding.Unicode.GetString(outBlock);
     }
}

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0

Date

History

Reason

December 2010

Added code example.

Customer feedback.

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