This is the method by which we can encrypt and
decrypt the data in the file. It is an important part of Security used in VB.Net application.
1.Open visual studio and create a project
2.Add the following assembly on the page
Imports
System.Security.Cryptography
Imports
System.Text
Imports
System.IO
3.Now write the following code
for Encryption and Decryption
Module
RC2Sample
Sub Main()
Try
Dim RC2alg As
RC2 = RC2.Create("RC2")
Dim sData As String = "My name is
yahoo"
Dim FileName As String = "CText.txt"
EncryptTextToFile(sData, FileName, RC2alg.Key, RC2alg.IV)
Dim Final As String = DecryptTextFromFile(FileName,
RC2alg.Key, RC2alg.IV)
Console.WriteLine(Final)
Catch e As
Exception
Console.WriteLine(e.Message)
End Try
Console.ReadLine()
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 RC2alg As
RC2 = RC2.Create
Dim cStream As New CryptoStream(fStream,
RC2alg.CreateEncryptor(Key, IV), CryptoStreamMode.Write)
Dim sWriter As New StreamWriter(cStream)
sWriter.WriteLine(Data)
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
Console.ReadLine()
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 RC2alg As
RC2 = RC2.Create
Dim cStream As New CryptoStream(fStream,
RC2alg.CreateDecryptor(Key, IV), CryptoStreamMode.Read)
Dim sReader As New StreamReader(cStream)
Dim val As String = sReader.ReadLine()
sReader.Close()
cStream.Close()
fStream.Close()
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
4.The
Encrypted file is store where the project is saved.