[AccessD] RC1 encryption - was Re: Field Level AES Encryption

Gustav Brock Gustav at cactus.dk
Fri Apr 29 10:07:53 CDT 2011


Oops John, you missed my follow-up message:

---
Hi all

I was told by one who knows more about encryption than me, Dave Howe, that:

<quote>
PC-1 is an important part of the DES algorithm, used to prescramble the bit ordering on the key (and remove the parity bits) before starting the first round of the non-invertible s-boxes. These are also left-rotated between each round (by 1 or 2 bits, in a non-regular pattern) to form what is commonly called a "key schedule" or "subkey array".

However your module is not using DES/PC-1, but "Pukall Code #1" which is a code Alexander Pukall designed himself - and which is widely regarded as insecure. Pukall shouldn't really have chosen the same name as the DES key schedule, as it does tend to cause confusion.
</quote>

So, as a general warning, the code is fine for making clear text non-readable but should not be used for true encryption.
---

/gustav


>>> jwcolby at colbyconsulting.com 29-04-2011 17:00 >>>
Thanks to Gustav.  this is encryption, not hashing.

Option Compare Database
Option Explicit

' PC1 Cipher 128-bit key
' (c) Alexander Pukall 1991






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