TripleDESCryptoServiceProvider Class
Updated: March 2012
Defines a wrapper object to access the cryptographic service provider (CSP) version of the TripleDES algorithm. This class cannot be inherited.
Assembly: mscorlib (in mscorlib.dll)
This algorithm supports key lengths from 128 bits to 192 bits in increments of 64 bits.
Note: |
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A newer symmetric encryption algorithm, Advanced Encryption Standard (AES), is available. Consider using the AesCryptoServiceProvider class instead of the TripleDESCryptoServiceProvider class. |
The following code example creates a TripleDESCryptoServiceProvider object and uses it to encrypt and decrypt data in a file.
Imports System.Security.Cryptography Imports System.Text Imports System.IO Module TrippleDESCSPSample Sub Main() Try ' Create a new TripleDESCryptoServiceProvider object ' to generate a key and initialization vector (IV). Dim tDESalg As New TripleDESCryptoServiceProvider ' Create a string to encrypt. Dim sData As String = "Here is some data to encrypt." Dim FileName As String = "CText.txt" ' Encrypt text to a file using the file name, key, and IV. EncryptTextToFile(sData, FileName, tDESalg.Key, tDESalg.IV) ' Decrypt the text from a file using the file name, key, and IV. Dim Final As String = DecryptTextFromFile(FileName, tDESalg.Key, tDESalg.IV) ' Display the decrypted string to the console. Console.WriteLine(Final) Catch e As Exception Console.WriteLine(e.Message) End Try End Sub Sub EncryptTextToFile(ByVal Data As String, ByVal FileName As String, ByVal Key() As Byte, ByVal IV() As Byte) Try ' Create or open the specified file. Dim fStream As FileStream = File.Open(FileName, FileMode.OpenOrCreate) ' Create a CryptoStream using the FileStream ' and the passed key and initialization vector (IV). Dim cStream As New CryptoStream(fStream, _ New TripleDESCryptoServiceProvider().CreateEncryptor(Key, IV), _ CryptoStreamMode.Write) ' Create a StreamWriter using the CryptoStream. Dim sWriter As New StreamWriter(cStream) ' Write the data to the stream ' to encrypt it. sWriter.WriteLine(Data) ' Close the streams and ' close the file. sWriter.Close() cStream.Close() fStream.Close() Catch e As CryptographicException Console.WriteLine("A Cryptographic error occurred: {0}", e.Message) Catch e As UnauthorizedAccessException Console.WriteLine("A file error occurred: {0}", e.Message) End Try End Sub Function DecryptTextFromFile(ByVal FileName As String, ByVal Key() As Byte, ByVal IV() As Byte) As String Try ' Create or open the specified file. Dim fStream As FileStream = File.Open(FileName, FileMode.OpenOrCreate) ' Create a CryptoStream using the FileStream ' and the passed key and initialization vector (IV). Dim cStream As New CryptoStream(fStream, _ New TripleDESCryptoServiceProvider().CreateDecryptor(Key, IV), _ CryptoStreamMode.Read) ' Create a StreamReader using the CryptoStream. Dim sReader As New StreamReader(cStream) ' Read the data from the stream ' to decrypt it. Dim val As String = sReader.ReadLine() ' Close the streams and ' close the file. sReader.Close() cStream.Close() fStream.Close() ' Return the string. Return val Catch e As CryptographicException Console.WriteLine("A Cryptographic error occurred: {0}", e.Message) Return Nothing Catch e As UnauthorizedAccessException Console.WriteLine("A file error occurred: {0}", e.Message) Return Nothing End Try End Function End Module
The following code example creates a TripleDESCryptoServiceProvider object and uses it to encrypt and decrypt data in memory.
Imports System.Security.Cryptography Imports System.Text Imports System.IO Module TrippleDESCSPSample Sub Main() Try ' Create a new TripleDESCryptoServiceProvider object ' to generate a key and initialization vector (IV). Dim tDESalg As New TripleDESCryptoServiceProvider ' Create a string to encrypt. Dim sData As String = "Here is some data to encrypt." ' Encrypt the string to an in-memory buffer. Dim Data As Byte() = EncryptTextToMemory(sData, tDESalg.Key, tDESalg.IV) ' Decrypt the buffer back to a string. Dim Final As String = DecryptTextFromMemory(Data, tDESalg.Key, tDESalg.IV) ' Display the decrypted string to the console. Console.WriteLine(Final) Catch e As Exception Console.WriteLine(e.Message) End Try End Sub Function EncryptTextToMemory(ByVal Data As String, ByVal Key() As Byte, ByVal IV() As Byte) As Byte() Try ' Create a MemoryStream. Dim mStream As New MemoryStream ' Create a CryptoStream using the MemoryStream ' and the passed key and initialization vector (IV). Dim cStream As New CryptoStream(mStream, _ New TripleDESCryptoServiceProvider().CreateEncryptor(Key, IV), _ CryptoStreamMode.Write) ' Convert the passed string to a byte array. Dim toEncrypt As Byte() = New ASCIIEncoding().GetBytes(Data) ' Write the byte array to the crypto stream and flush it. cStream.Write(toEncrypt, 0, toEncrypt.Length) cStream.FlushFinalBlock() ' Get an array of bytes from the ' MemoryStream that holds the ' encrypted data. Dim ret As Byte() = mStream.ToArray() ' Close the streams. cStream.Close() mStream.Close() ' Return the encrypted buffer. Return ret Catch e As CryptographicException Console.WriteLine("A Cryptographic error occurred: {0}", e.Message) Return Nothing End Try End Function Function DecryptTextFromMemory(ByVal Data() As Byte, ByVal Key() As Byte, ByVal IV() As Byte) As String Try ' Create a new MemoryStream using the passed ' array of encrypted data. Dim msDecrypt As New MemoryStream(Data) ' Create a CryptoStream using the MemoryStream ' and the passed key and initialization vector (IV). Dim csDecrypt As New CryptoStream(msDecrypt, _ New TripleDESCryptoServiceProvider().CreateDecryptor(Key, IV), _ CryptoStreamMode.Read) ' Create buffer to hold the decrypted data. Dim fromEncrypt(Data.Length - 1) As Byte ' Read the decrypted data out of the crypto stream ' and place it into the temporary buffer. csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length) 'Convert the buffer into a string and return it. Return New ASCIIEncoding().GetString(fromEncrypt) Catch e As CryptographicException Console.WriteLine("A Cryptographic error occurred: {0}", e.Message) Return Nothing End Try End Function End Module
System.Security.Cryptography.SymmetricAlgorithm
System.Security.Cryptography.TripleDES
System.Security.Cryptography.TripleDESCryptoServiceProvider
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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.
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