Encryption Algorithms

[chemicalNova]

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

[dglienna]

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.

[chemicalNova]

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

[dglienna]

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

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

[chemicalNova]

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

chem

[StrangerInBeijing]

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 (http://www.devx.com/security/Article/17455)

[wossname]

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.

[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

[StrangerInBeijing]

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