Re: Data Encyption

From: Joe Williams (JOE_at_ANYWHERE.com)
Date: 12/18/04 

Date: Fri, 17 Dec 2004 23:27:06 -0500

Hi, Thanks for the great reply. I did a quick search and came up with this
code, it says it is Vignere with XOR? It is a really lightweight function,
is this giving me the bang for the buck that I need?

Public Function VignereCode(ByVal InText As String, ByVal Password As
String) As String
'uses the vignere method with XOR. Can decode as well as encode
Dim i As Long, j As Long
Dim s As String
j = 0
If Len(Password) Then
    For i = 1 To Len(InText)
        s = s & Chr$(Asc(Mid$(InText, i, 1)) Xor Asc(Mid$(Password, j + 1,
1)))
        j = (j + 1) Mod Len(Password)
    Next i
Else
    For i = 1 To Len(InText)
        s = s & Chr$(&HFF Xor Asc(Mid$(InText, i, 1)))
    Next i
End If
VignereCode = s
End Function

THanks

Joe
<aatcbbtccctc@yahoo.com> wrote in message
news:1103342547.359086.281480@c13g2000cwb.googlegroups.com...
>
> Joe Williams wrote:
>
>> I have some data in tables regarding system setup parameters that I
> would
>> rather the user not be able to see or manipulate.
>>
>> After experimenting with ways to hide tables, i stumbled across the
> AES
>> encryption, which allows you to encrypt data in an access table.
>>
>
>
>> My question is, what issues should I be aware before i try to
> immplement
>> this in my application?
>
> Using AES is overkill for the need you describe. Go with a simple XOR
> cipher. Unfortunately I do not have a URL handy. Some googling should
> find one for you, easily.
>
>
>> How secure is the encryption?
>
> Er, given that AES is the new US government standard?
>
>
>> It looks as if you need a key to unencrypt or encrypt the data.
>
> If you didn't, there wouldn't be much point to it, would there!
>
>
>> If I hard code the encryption key and make the DB an MDE, that would
> seem to be pretty secure, right?
>
> Wrong. If the key occupied contiguous bytes (or unicode double-bytes)
> within the file, it could be found by a simple "sliding window" attack.
> Not that your users would be likely to try that :-)
>
>>
>> Any thoughts on encryption?
>
> Yes. A simple scheme requiring 10% effort, will deter 99% of the people
> who you want to deter. *No amount* of extra effort, will deter the
> remaining 1%.
>
> HTH,
> TC
>
>
>>
>> Thanks
>>
>> Joe
>

Relevant Pages

  • Encryption A97
    ... I've been playing with some encryption code from the web ... and have been pleased with this sample code from Rob Bovey. ... Essentially it takes a string and puts it through an XOR process and saves ...
    (microsoft.public.access.modulesdaovba)
  • Re: Encrypt String
    ... >> if you do not publish the protection string, ... > with basic cryptography knowledge should be able to glean the encryption ... And being a symmetrical algorithm, ... XOR scheme. ...
    (microsoft.public.dotnet.languages.csharp)
  • Re: Preventing large runs of identical bits.
    ... way I can xor the xor result, and repeat that process X times, so that ... the chance of that input string creating a constant bit string ... I'm using it for an encryption algorithm I'm writing, ... I'm asking it in the compression newsgroup rather than an encryption ...
    (comp.compression)
  • Re: Preventing large runs of identical bits.
    ... way I can xor the xor result, and repeat that process X times, so that ... the chance of that input string creating a constant bit string ... I'm using it for an encryption algorithm I'm writing, ... I'm asking it in the compression newsgroup rather than an encryption ...
    (comp.compression)
  • Re: ECB-Counter AES mode
    ... sequential counter value over the plain text block with XOR prior ... to AES encryption and removing the counter value after AES ... not removing the correlation entirely. ... xoring into the plaintext and xoring the hash out after the encryption. ...
    (sci.crypt)
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