quick, semi-secure encryption/decryption?

[softwareguy74]

Hi,

I have a 2MB text file that I need to be able to encrypt/decrypt quickly so the user does not have to wait too long..

The idea is to just keep the casual user from looking at the text file directly.. If a hacker can crack the code, then oh well.. No biggy.. My priority is speed and then encryption..

As an alternative, is it possible to compile a text file within the executable? The text will not ever change.. Probably not, but I just thought I'd ask..

I used the CryptoAPI module found at freevbcode.com but it took so long it locked up my computer..

When replying, please keep in mind that I'm new to this subject so I need example code to go along with your suggestions..

Thanks,

Dan

[HeSaidJoe]

'Encrypt/Unencrypt a file
'
Option Explicit
'
Private Function EncryptFile(sFile As String, iKey As Integer)

    Dim iFake#
    Dim x As String * 1
     
    Dim lP As Long, z
    Dim intNum#
    intNum = FreeFile

    iFake = Rnd(-1)
    Randomize (iKey)
     
     
    lP = 1
    Open sFile For Binary As intNum
     
    While lP <= LOF(intNum)
     
    Get #intNum, lP, x
     
    z = Asc(x) + Int(Rnd * 256)
    If z > 255 Then z = z - 256
     
    x = Chr(z)
     
    Put #intNum, lP, x
     
    lP = lP + 1
     
     
    Wend
     
    Close #intNum

    MsgBox "Your file has been encrypted."

End Function


Private Function DecryptFile(sFile As String, iKey As Integer)

    Dim iFake As Integer
    Dim x As String * 1
     
    Dim lP As Long, z
    Dim intNum#
    
    intNum = FreeFile
  
    iFake = Rnd(-1)
    Randomize (iKey)
     
     
    lP = 1
    Open sFile For Binary As #intNum
     
    While lP <= LOF(intNum)
     
    Get #intNum, lP, x
     
    z = Asc(x) - Int(Rnd * 256)
    If z < 0 Then z = z + 256
     
    x = Chr(z)
     
    Put #intNum, lP, x
     
    lP = lP + 1
     
    Wend
     
    Close #intNum
    
    MsgBox "Your file has been unencrypted."
    
End Function

' <<<<   Form Event Code    >>>>


Private Sub Command1_Click()
'encrypt the file
    Call EncryptFile("C:\myFile.txt", 44)

End Sub

Private Sub Command2_Click()
'decrypt the file
    Call DecryptFile("c:\myFile.txt", 44)

End Sub

[softwareguy74]

Thanks! works great..

Now, how would I modify it to just decrypt it into memory into a string variable while leaving the actual file encrypted?

Thanks,

Dan