Encryption !!!

[MrPolite]

I know that I have to use System.Security.CreateEncryptor
but can someone plz give me an example?
Lets say I have a text file and I want to encrypt the data in the file by using a "key" for the enctyption. How can I do that?

I will appriciate if anyone can show a little example for me, I cant figure it out

[Evad]

I saw this thread and it made me think, so after a few hours I came up with this....

Create a new vb app and add a module, erase all the pre generated code and place this code inside... then on the properties of the form set the "startup object" to point to sub main

Imports System
Imports System.Text
Imports System.Security.Cryptography

Module Module1

  Private RSA As New RSACryptoServiceProvider()
  Private KeyInfo As RSAParameters = RSA.ExportParameters(False)
  Private AE As ASCIIEncoding = New ASCIIEncoding()

  Sub Main()
    Dim StrToEncode As String = "This is the text that will be encrypted."
    Dim EncodedStr() As Byte ' This is the Array that will hold the Encrypted Data


    ' Display the Test to be encrypted
    MsgBox("String To Be Encrypted:" & vbCrLf & vbCrLf & StrToEncode)

    ' Encode the Data
    EncodedStr = DataEncrypt(StrToEncode)

    ' Do something with this Encrypted Data
    MsgBox("String Encoded:" & vbCrLf & vbCrLf & AE.GetString(EncodedStr) & vbCrLf & vbCrLf)

    ' Decode the Data
    StrToEncode = DataDecrypt(EncodedStr)

    'Display the Decrypted String to a Message Box
    MsgBox("String Decoded:" & vbCrLf & vbCrLf & StrToEncode)
  End Sub

  Private Function DataEncrypt(ByVal RawData As String) As Byte()
    Dim ByteArray() As Byte = AE.GetBytes(RawData)
    DataEncrypt = RSA.Encrypt(ByteArray, False)
  End Function

  Private Function DataDecrypt(ByVal RawData As Byte()) As String
    Dim ByteArray() As Byte = RSA.Decrypt(RawData, False)
    DataDecrypt = AE.GetString(ByteArray)
  End Function

  Private Function GetParamVal(ByVal RawData As Byte()) As String
    Dim i As Integer = 0
    GetParamVal = "{"
    For i = 0 To UBound(RawData)
      If i = UBound(RawData) Then
        GetParamVal = GetParamVal & RawData(i)
      Else
        GetParamVal = GetParamVal & RawData(i) & ", "
      End If
    Next
    GetParamVal = GetParamVal & "}"
  End Function

End Module

I didn't have the time to write the extra code that needs to save the "KeyInfo" data but I wrote a function that can turn each member of the class into a string for storage just call the GetParamVal function with the KeyInfo.propertyname and it will return the property in a string type, if you wish to access the encrypted data you will need the exact keyinfo data when the string was encrypted.

Hope this helps, if not well at least I learned something about encryption....

[Thelonius]

Another thing you could do is use the HashTable class to create your own encryption scheme.