TripleDES Class
Assembly: mscorlib (in mscorlib.dll)
'Declaration <ComVisibleAttribute(True)> _ Public MustInherit Class TripleDES Inherits SymmetricAlgorithm 'Usage Dim instance As TripleDES
/** @attribute ComVisibleAttribute(true) */ public abstract class TripleDES extends SymmetricAlgorithm
ComVisibleAttribute(true) public abstract class TripleDES extends SymmetricAlgorithm
TripleDES uses three successive iterations of the DES algorithm. It can use either two or three 56-bit keys.
This algorithm supports key lengths from 128 bits to 192 bits in increments of 64 bits.
The following code example method uses TripleDESCryptoServiceProvider with the specified key (Key) and initialization vector (IV) to encrypt a file specified by inName. It then outputs the encrypted result to the file specified by outName.
Private Shared Sub EncryptData(inName As String, outName As String, _ tdesKey() As Byte, tdesIV() As Byte) 'Create the file streams to handle the input and output files. Dim fin As New FileStream(inName, FileMode.Open, FileAccess.Read) Dim fout As New FileStream(outName, FileMode.OpenOrCreate, _ FileAccess.Write) fout.SetLength(0) 'Create variables to help with read and write. Dim bin(100) As Byte 'This is intermediate storage for the encryption. Dim rdlen As Long = 0 'This is the total number of bytes written. Dim totlen As Long = fin.Length 'This is the total length of the input file. Dim len As Integer 'This is the number of bytes to be written at a time. Dim tdes As New TripleDESCryptoServiceProvider() Dim encStream As New CryptoStream(fout, _ tdes.CreateEncryptor(tdesKey, tdesIV), CryptoStreamMode.Write) Console.WriteLine("Encrypting...") 'Read from the input file, then encrypt and write to the output file. While rdlen < totlen len = fin.Read(bin, 0, 100) encStream.Write(bin, 0, len) rdlen = rdlen + len Console.WriteLine("{0} bytes processed", rdlen) End While encStream.Close() End Sub
private static void EncryptData(String inName, String outName,
ubyte tdesKey[],ubyte tdesIV[])
{
//Create the file streams to handle the input and output files.
FileStream fin = new FileStream(inName, FileMode.Open,
FileAccess.Read);
FileStream fout = new FileStream(outName, FileMode.OpenOrCreate,
FileAccess.Write);
fout.SetLength(0);
//Create variables to help with read and write.
ubyte bin[] = new ubyte[100];//This is intermediate storage for the
//encryption.
long rdlen = 0; //This is the total number of bytes written.
long totlen = fin.get_Length(); //This is the total length
//of the input file.
int len; //This is the number of bytes to be written at a time.
TripleDESCryptoServiceProvider tdes =
new TripleDESCryptoServiceProvider();
CryptoStream encStream = new CryptoStream(fout,
tdes.CreateEncryptor(tdesKey, tdesIV), CryptoStreamMode.Write);
Console.WriteLine("Encrypting...");
//Read from the input file, then encrypt and write to the output file.
while ((rdlen < totlen)) {
len = fin.Read(bin, 0, 100);
encStream.Write(bin, 0, len);
rdlen = rdlen + len;
Console.WriteLine("{0} bytes processed",
System.Convert.ToString(rdlen));
}
encStream.Close();
} //EncryptData
Decryption can be handled in the same way; use CreateDecryptor instead of CreateEncryptor. The same key (Key) and initialization vector (IV) used to encrypt the file must be used to decrypt it.
System.Security.Cryptography.SymmetricAlgorithm
System.Security.Cryptography.TripleDES
System.Security.Cryptography.TripleDESCryptoServiceProvider
Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
Reference
TripleDES MembersSystem.Security.Cryptography Namespace