Encryption Algorithms

Howdy all,

I'm wondering if there are any tutorials anyone has come across regarding advanced text encryption. I want to see how uncrackable I can get a small text file.

Hopefully I can possibly transpose this onto pictures aswell.

Thanks in advance,

chem

I like to use Capicom, which Microsoft released. It encrypts differently each time, based on the time. It decrypts perfectly! You can google it.

I haven't encrypted files, but I'm pretty sure it would be possible. I have only encrypt text strings.

I really only want to encrypt text strings (in turn, the text files). Can you provide any articles which have some algorithms or theory behind text encryption?

chem

You mean other than Capicom? This is something that I have also used.

VB Code:

Dim ff As Integer
Public st As String
 
Private Sub Form_Load()
    ff = FreeFile
    Dim strBuff As String
    ff = FreeFile
    Open App.Path & "/site.txt" For Input As #ff
    Do Until EOF(ff)
       Line Input #ff, strBuff
    Loop
    Close #ff
    Text1.Text = RC4ED(strBuff, "837ufhjjkddQR13%^&*&@#$&9ASFewFDAAW!%9367")
    Call WriteFile
End Sub
 
Sub WriteFile()
 ff = FreeFile
    Open App.Path & "\site.txt" For Output As #ff
        Print #ff, Text1.Text ' <-- Might need to use Write # to add quotes
    Close #ff
End Sub
 
Function RC4ED(InString As String, password As String) As String
 
    Dim S(0 To 255) As Integer
    Dim K(0 To 255) As Integer
    Dim I As Integer, j As Integer, tmp As Integer
    Dim t As Integer
    Dim outstring As String
 
 
    For tmp = 0 To 255
        S(tmp) = tmp
        K(tmp) = Asc(Mid(password, 1 + (tmp Mod Len(password)), 1))
    Next
 
 
    For I = 0 To 255
        j = (j + S(I) + K(I)) Mod 256
        Swap S(I), S(j)
    Next
 
    I = 0
    j = 0
    outstring = ""
 
 
    For tmp = 1 To Len(InString)
        I = (I + 1) Mod 256
        j = (j + S(I)) Mod 256
        Swap S(I), S(j)
        t = (S(I) + S(j)) Mod 256
        outstring = outstring & Chr((mXor(S(t), Asc(Mid(InString, tmp, 1)))))
    Next
 
    RC4ED = outstring
End Function
 
 
Function mXor(I As Integer, j As Integer) As Integer
 
 
    If I = j Then
        mXor = j
    Else
        mXor = I Xor j
    End If
 
End Function
 
 
Sub Swap(ByRef a As Integer, ByRef b As Integer)
 
    Dim t As Integer
    t = a
    a = b
    b = t
End Sub

Here's a link. Run the program twice. First time encrypts, second time decrypts.
http://vbforums.com/attachment.php?attachmentid=37573

Thanks for that DG, can start to fiddle with some things now :D

chem

I did not use it for a while, but you got encryption build into .Net

Check this out for a starter: RSA in VB.NET

VS.net has a whole namespace full of encryption classes. Gives you full control of everything. You won't get any much more uncrackable than that.

I kinda want to see how far I can go with my own. I also hoped to make a voice recognition decryption. The person says the password, and the text is decrypted. I might actually look alot deeper than I originally was for this..

Ta though :)

chem

Quote:

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Originally Posted by chemicalNova

I kinda want to see how far I can go with my own. I also hoped to make a voice recognition decryption. The person says the password, and the text is decrypted. I might actually look alot deeper than I originally was for this..

Ta though :)

chem

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huh? whatever you are smoking, I want some too!