Mega Code Archive
CryptoStream Class Defines a stream that links data streams to cryptographic transformations
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Imports System.Security.Cryptography
Imports System.Text
Imports System.IO
Module RijndaelSample
Sub Main()
Try
Dim RijndaelAlg As Rijndael = Rijndael.Create
Dim sData As String = "this is a test."
Dim FileName As String = "CText.txt"
EncryptTextToFile(sData, FileName, RijndaelAlg.Key, RijndaelAlg.IV)
Dim Final As String = DecryptTextFromFile(FileName, RijndaelAlg.Key, RijndaelAlg.IV)
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
Dim fStream As FileStream = File.Open(FileName, FileMode.OpenOrCreate)
Dim RijndaelAlg As Rijndael = Rijndael.Create
Dim cStream As New CryptoStream(fStream, _
RijndaelAlg.CreateEncryptor(Key, IV), _
CryptoStreamMode.Write)
Dim sWriter As New StreamWriter(cStream)
Try
sWriter.WriteLine(Data)
Catch e As Exception
Console.WriteLine("An error occurred: {0}", e.Message)
Finally
sWriter.Close()
cStream.Close()
fStream.Close()
End Try
Catch e As Exception
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
Dim fStream As FileStream = File.Open(FileName, FileMode.OpenOrCreate)
Dim RijndaelAlg As Rijndael = Rijndael.Create
Dim cStream As New CryptoStream(fStream, _
RijndaelAlg.CreateDecryptor(Key, IV), _
CryptoStreamMode.Read)
Dim sReader As New StreamReader(cStream)
Dim val As String = Nothing
Try
val = sReader.ReadLine()
Catch e As Exception
Console.WriteLine("An Cerror occurred: {0}", e.Message)
Finally
sReader.Close()
cStream.Close()
fStream.Close()
End Try
Return val
Catch e As Exception
Console.WriteLine("A file error occurred: {0}", e.Message)
Return Nothing
End Try
End Function
End Module
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